So, I actually am very pleased with the new Deathwatch codex and am excited to try it out, both as an allied element to my current armies and even potentially as an entirely new army in its own right (I particularly like the fact that, unlike the Harlequin or Militarum Tempestus codexes, I think you really do have the ability to run a competitive force using just this book, without any allies).
That said, I also love coming up with experimental rules/improvements, even for the best armies and even for books that just came out (or, in the case of Codex: Deathwatch, are not even officially out yet 😉 ). Based on that, I think Codex: Deathwatch is great, but I also think GW missed a few opportunities and also had a few things that ought to be Errata-ed…. so, here is my “wish list” for improving the, still not even officially released, Deathwatch codex:
 – WATCH SERGEANT/BLACK SHIELD OPTIONS FOR BIKES, VANGUARD, AND TERMINATORS — I think these two characters provide a lot to the DW Veteran squads and would be fluffy, fun, and competitive options for these squads. Can you imagine a Black Shield Terminator or Vanguard Vet going to town against a Monstrous Creature or IC with WS5 and double attacks as these squads storm into combat? Also, a character/sergeant option, with access to Special Issue Wargear and unique “Xenos Weapons” (see below) in all of these squads would make them even more customizable/flexible, which is great for the army.
 – DW TECHMARINE (HQ) AND DW APOTHECARY (VETERAN SQUAD UPGRADE) OPTIONS — Not only are these two very prevalent in the Deathwatch fluff, as many have pointed out recently, but they would provide further flexibility and diversity to the army. The DW Techmarine could repair vehicles, tank AP3 shooting with his AA, and have a special Cognitar wargear that grants a friendly nearby unit +1BS, making him a force-multiplier for DW squads, and the Apothecary upgrade could ensure that the relatively fragile DW Veterans have a little more survivability (and that their precious Gene-Seed gets back safely to their parent chapters, fluff-wise).
 – HEAVY WEAPON CHANGES — The unique DW Frag Cannons and Infernus Heavy Bolters are brilliant, being both unique to the Deathwatch and competitive/versatile. I would keep these two, but drop the Heavy Flamer and Heavy Bolter options (redundant with the Infernus Heavy Bolter) and modify the Missile Launcher into the “Beowulf Pattern Missile Launcher” for +25 points, with multiple special ammo types “organic” to the Missile Launcher
(a) Firefang Missiles – 48″ S4 AP5, Small Blast, Ignore Cover
(b) Ironspear Missiles – 48″ S8 AP2, Sunder
(c) Skyfury Missiles – 48″ S7 AP3, Skyfire, Interceptor
(d) Venomcraft Missiles – 48″ S2 AP3, Fleshbane
Just like Special Issue Ammo for Bolters, this would give Deathwatch a superior, multi-purpose Missile Launcher that could fulfill multiple functions and allow them to be competitive, despite their high points cost/small army size.
 DIVERSIFIED XENOS BLADE OPTIONS — I think making the “Xenos Blades” that are available to Watch Captains and Watch Sergeants into more varied types would be fluffy and competitive, as each Watch Captain and Watch Sergeant (Veteran, Vanguard, Biker, or Terminator type) able to pick a “Xenos Blade” type that works for them:
(a) Necron Phase Blade (25 points) — S:User AP3, Shred, Molecular Re-alignment Field (enemy units must re-roll successful Invul saves against this weapon)
(b) Eldar Void Lance (30 points) — S:+1 AP1, Lance (on the charge); S: User AP4, Lance (after the charge)
(c) Tau Fusion Axe (30 points) — S:+1 AP2, Armourbane, Bulky (user always strikes at I2 when using this weapon)
(d) Tyranid Venomspine (20 points) — S:X AP-, Fleshbane, Whiplash (+1I/+1A to bearer when using this weapon)
Not only would this give diverse options to the DW leaders, but it would also represent how the Deathwatch pragmatically makes use of any effective weapons it gets it hands on, even weapons taken from the Xenos enemy.
 HQ UPGRADES —
(a) Watch Captain — I would allow him to take a Space Marine Bike in addition to the AA and Jump Pack options and I would also give him the option to purchase Blind Grenades (5 points). I would also give the Watch Captain (not wearing TDA, of course) access to the Special Weapons wargear list (i.e. so he could take a DW Shotgun, Stalker Boltgun, Flamer, etc.), enabling the build of a more “shooty” HQ and also making the Banebolts of Eryxia Relic actually useable with the Stalker Boltgun.
(b) DW Chaplain — I would allow him to take a Jump Pack and have the option to purchase Rad grenades (+15 points).
(c) DW Techmarine — I would allow him to take a Space Marine Bike and to purchase Haywire grenades (+5 points).
(d) DW Librarian — I would allow him to purchase Psykout Grenades (+5 points).
All of these upgrades would give a little more versatility to the various HQs, while also providing unique reasons to be included in a DW army/lead different elements of that army (i.e. the JP Chaplain could lead Vanguard Vets, the TDA Librarian could attach to Terminators, the Techmarines could lead a squad of DW Bikers, and the Watch Captain could be configured for any role).
 WATCH MASTER UPGRADES —
(a) Indomitable Commander Rule — I would give the Watch Master a special rule called “Indomitable Commander” which grants him and any Deathwatch models in his squad the Relentless USR. This allows him to shoot his Guardian Spear and still charge in the same turn and also makes him a enhanced force multiplier for shooty DW squads or Kill Teams that he is attached to.
(b) Orbital Array Option — I would also allow the Watch Master to purchase a miniature Orbital Array for +35 points (like the Rhino Primaris, this would allow him to call down a One Use Only Orbital Bombardment and, starting turn 2, bring one friendly unit in from Reserve automatically each turn).
 VEHICLE UPGRADES —
(a) DW Land Raiders — I would allow any DW Land Raider variant to be able to purchase Armoured Ceramite, Refractor Fields (gives vehicle a 5++), and/or Enhanced Cognitars (gives +1BS when shooting, including to Snap Shots, so BS5 normally and BS2 for Snapshots) in addition to their “normal” options. I think these options would reflect the Deathwatch’s access to unusual/superior wargear compared to other Space Marines and also would make the Land Raider variants much more viable/competitive options game-wise (i.e. better survivability, better firepower, etc.)
(b) DW Dreadnoughts/Venerable Dreadnoughts — I would give these two the option to purchase a Veteran Skill upgrade (Venerable Dreads could purchase two of them) that gives the Dreadnought either 1) Interceptor; 2) Tank Hunter/Monster Hunter; 3) or Hatred/Fleet. This hearkens back a bit to the old Veteran skills that Dreadnoughts used to be able to get, many editions ago, and I think would be particularly useful for DW Dreads, both to make them unique from their “vanilla” counterparts and to provide some flexibility to their role in the force. Finally, instead of the normal Missile Launcher, DW Dreads/VDs would be able to replace their PF/SB with a Beowulf Pattern Missile Launcher with all four types of Missiles (see above).
(c) DW Rhinos/Razorbacks — I would allow both of these vehicles to be able to purchase a Locator Beacon, in addition to their normal Wargear options, and come with the Scout USR as part of their Special Rules. I think this would make both vehicles more viable, especially compared to the Drop Pod and Corvus Blackstar, and thus have more reason to be fielded. Weapons-wise, I would allow DW Rhinos the option to purchase a Pintle-mounted Infernus Heavy Bolter and I would allow the DW Razorback, in addition to the TLed Heavy Bolter/Assault Cannon/Lascannon options it currently has, to alternately take a TLed DW Frag Cannon. These would be fluffy with respect to Deathwatch-specific gear, would give these vehicles more versatility in gameplay, and would further distinguish the DW faction as a whole from the other Marine-type armies.
 ADD CEREBERUS FIRE SUPPORT DROP POD (HEAVY SUPPORT CHOICE) — Kind of like the Deathstorm Drop Pod, but instead of deploying Assault Cannons or Whirlwind Launchers, this would mount an automated Thunderfire Cannon which could provide artillery support to the Deathwatch units all game long, starting turn 1. Not only would this give a little more variety/flavor to the Heavy Support section of the Codex, but I think it would be a fluffy addition and also a competitive one to the entire Deathwatch faction as a whole.
 CHANGES TO DW VETERANS, DW BIKERS, AND DW VANGUARD —
(a) DW Veterans — All models in squad (including Watch Sergeant and Black Shield) gain a Bolt Pistol for free, in addition to their other “baseline” Wargear. This makes them more versatile and helps account for the fact that the entire army has a very high base model price, even for the “cheapest” units.
(b) DW Bikers — All models in squad (including Watch Sergeant and Black Shield) gain a Bolt Pistol for free, in addition to their other “baseline” Wargear. Additionally, the bikers gain Infiltrate USR for free (would apply to any Kill Team they are a part of as well). This makes them more versatile and lethal in close combat for their points (see above about DW Veterans) and also enhances their flexibility, especially pre-deployment, allowing them to maximize the contributions of their DW Teleporter Homers.
(c) DW Vanguard — Gain Scout USR for free (would apply to any Kill Team the are a part of as well). This provides them enhanced deployment versatility and helps emphasize their mobility, which is one of the key reasons they exist beyond the normal DW Veteran squads, furthering enhancing their “unique” role in the army.
 SPECIAL ISSUE AMMUNITION FOR STORM BOLTERS — Any Deathwatch models using Storm Bolters, be they characters in TDA, DW Veterans with the SB upgrade, or DW Terminators, would get access to the following Special Issue Ammunition to use with the Storm Bolters:
—Dragonfire Bolts — 24″ S4 AP5 Assault 2, Ignore Cover
—Hellfire Bolts — 24″ S1 AP5 Assault 2, Poisoned (2+)
—Kraken Bolts — 30″ S4 AP4 Assault 2
—Vengeance Bolts — 18″ S4 AP3 Assault 2, Gets Hot