The tech tree is way to small, it leaves only 2-3 tactics for each race. My suggestions: (I'm using Orks as an example, but this can apply to all races)
- Each leader should have its own playing style more pronounced, a stealth army should be really stealth based, an offense army should be based on offense have have defensive disadvantages. (example: choosing the offensive based Warboss will give you cheaper Sluggaz and Nobz, on top of his abilities, choosing the defensive based Mek will give you cheaper Big Shoota upgrades etc etc)
- Expand on the tech tree - there aren't enough units to give DoW2 enough longevity, I suggest a 4th tier
- Offer units that can be taken as an option, sort of like Tau in DC, you choose Kauyen or Mont'ka. (example: more Orks addon, or tougher Orks addon. One option making Orks cheaper and higher in number, the other giving the player the ability to build Mega armoured nobz + a health bonus to all orks) good for a tier 4 IMO, many games don't even finish because armies aren't powerful enough to destroy an HQ before they run out of VP.
This would offer a unique style of play that can be chosen by the player to meet his tactical demands (example: out numbering the already low in number Marines, as opposed to trying to toughen your Orks up and meet them head on)
right now the game (it's beta i know) is way to bland, It doesn't have nearly as much tactical options as DC did, or even Coh.