OP: problem is not the message you want to transmit, rather than the title of the thread. People will just read allies OP.
The thing is, this is how the allied factions were designed and are meant to be played at the moment. If you want things to be changed, then you'll have to mirror the factions even more. Remove whatever aggro tools allies have early on, while improving drastically the scaling and late game, while buffing early game while nerfing the late game scaling. This is not worth doing IMO.
Point is: allies (not UKF) are aggresive by nature, and aggresive play means you have initiative. Point is, there's no reason to not play aggro as the alternatives are worst.
Same can be said for the opposite side, mostly OH. They are not designed as aggro factions, and benefit the most of dragged games.
I fail to see where skill cap is lower, do you have arguments ?
More like APM required to perform at certain level above average. By nature, it's easier for 95% of the population to play on the defensive with small number of stronger troops than control several more weaker units and be aggresive.