Most times when any of us mention v4 it is about wwh40k TABLETOP GAME!! Don't get too excited

For someone who's hardly played the tabletop game, you did a damn fine job with the TD. All you have to do is watch out, especially in this forum, about rules and copyright names. GW is very stingy and like to sue people for stuff, as I lernt at
www.40konline.com (i didn't get sued, but I was told they couldn't give away rules because GW protects thm very closly). I think however a TD would be somewhat harmless for GW and they'll let it slip, but I do not know the inner workings of Citadel minitures and GW. This is just a cautionary tip.
Now about subraces. Necrons, Dark Eldar and Tau (maybe you can get away with Orks too) don't need subraces. However; Space Marines, IG, Eldar, Chaos and Tyrinids do need subraces for complete understanding of each race.
My tip to you:
For Space Marines
Have an upgrade for dreadnaught to 'veneralbe dreadnaught' which has increased damage and bonus to mechanical (unless that's already there). Add the Predator tank, you don't need Rhinos as they are transports in the game. Maybe add the whirlwind multi missile launcher

Include Ultramarines, who are the normal 'codex' chapter and basically have good shooting but also good close combat, so they are you space marines as they are. Hero unit: Maranus Calgar.
Blood Angles are experts at closecombat, give them bloodlust for sure! Also their hero unit should be the Furuso Dreadnaught (or an upgrade from a normal dready) and the other blood Angles heroes who's names I don't know.
Black Templars, hero unit 'emperors champion' and call their terminators sword breatheren (forgive me GW).
Space wolves, hero unit 'leman russ tank' (trust me).
For Eldar, speak to an eldar player, but please include the 'Falcone Grav Tank' with an upgrade to Fire Prisim Tank.
For Tau, wait for the new codex 'Tau empire' to come out them read through that and select some other alien races. Also give the crisis battle suit weapon and hardpoint options if you can.
Dark Eldar are good as they are. Well done!
Tyrinids need a few Biomorphs;, but your best option is to go to
www.forgworld.com and look through the Tyrinid Titans for hero Ideas. The red terror and old one eye do not exist... Tyrinids need melee attacks, especially for the genestealers!
Orks need melee attacks to make them tougher. Maybe include an upgrade for boyz as Nob (or a seperate unit) and he can have command aura. You should have an upgrade for boyz to big shoota boy and he will shoot fast piercing shots, however he needs to miss a fair few times. All orks suck at shooting. Hero ideas: Looted vehicle. Keep Gukazul (can't spell his name)
Necrons are pretty good as they are. try making the skeletons loo, more greyish though
Any races I've left out just ask

Best of luck!
PS add something in the credits for GW because they might get stingy. IE say: Map made by (insert name here) All names and concepts are copyright of Games Wrokshop, see
www.games-workshop.com for more details.