So I'm going to get the small one out of the way first.
Probably one of my biggest gripes right now is the fact that the UI is too tooltip-y. While I understand from a visual perspective why less UI can be good, there's a lot of information that I personally find crucial that was displayed in previous DoW titles that isn't anymore. Most noticably, seeing a unit's actual numeric health value requires a tooltip hover, and seeing your requisition and power income rates also requires a tooltip hover. Having elite points show how long until the next one constantly rather than hiding it away under a tooltip may help as well. I think if nothing else a unit portrait + health should appear when you select a unit, perhaps over the current location of the advanced commands area or next to the command card, and it should apply both to elite and non-elite units. I wasn't even aware units were healing slowly outside of combat until I hovered over one to see its' health slowly increasing due to it being hidden away, and frankly, that would have been a helpful thing to know, as would knowing your current income on the resources - constantly.
Now the big one.
Also, while I'm sure it's been said, the lack of even a basic annihilation game mode is a bit ridiculous. I don't think the new game mode is bad, not at all, but it shouldn't be the only option for playing the game outside of the campaign. Even the VP-centric Dawn of War 2 launched with a basic annihilation mode on the side in case you got sick of capturing points, and likewise, having a mode where it was a classic base-on-base system rather than going against a power core moba style would be great to have and I doubt that hard to implement, much like how in DoW 2, annihilation simply removed the victory points from the map and called it a day. It's a simple fact that there will be a LOT of negative backlash on the game for not allowing players to do anything other than a moba style mode, and a lot of lost sales from people who won't buy into a game that is effectively force feeding it to them if they want to play at all - this isn't a "try it, you'll like it" situation, it's a case where if potential buyers look at the game and see it doesn't have standard RTS game modes at all, they won't give it a shot, they'll simply look away and forget about it. Even if it's added post launch, too many people will have already forgotten about the game or marked it down and it will hurt this game's long-term life and sales a lot - look at No Man's Sky as an example of a game that's adding much needed features post launch but has already long since died and been forgotten by both those who bought it and those who might have since it hurt itself too badly by not including it at release.
And as for preventing rushing in the game, just toss 2 or 3 turrets down outside of every HQ in annihilation. I saw that standard turrets like the heavy bolter turret actually exist through the gameplay demos, so just stick some down by the HQs for annihilation like with Company of Heroes 1 and 2 and Dawn of War 2 both did and you solve the issue of rushing.