I would welcome if you, Bioware, would stop measuring your targeted sales on Skyrim and also would stop to streamline your games for the wide masses.
I would like you to return to the roots of ME1, add more Rpg-Elements (like more skills and a wider Variation for each class and also items like armors and an inventory, so thet players can customise their character and theit party). I know Mr. Hilleman thinks games have to be easy as tic tac toe, but that's not true. A bit of complexity adds to a games appealing - especially if it's an Rpg, because it leaves room for experimentation and by so adds replay-value.
Also i would like to see some new, neverseen features... something like space combat (eventhough i know this is unlikely).
I would also like, if combat varied a bit more. Frankly spoken, most of the time the ME-combat feels like: start mission, go to cover, enemy spawn, shoot, shoot, shoot - use skill - shoot, shoot, shoot, all dead, go a few steps further rinse and repeat.
Why not adding something like destructable cover... or cover, that can be also used to attack (like throwing crates through biotics... or perhaps you throw a grenade to a crystal-pylon and the explosion destroys it and turns the shards into shrapnell).
Also i liked that security-bots in ME2 had different hitzones so you could destroy heir legs and still they would fight) and i would like to see more enemies like that... maybe some robot or ferocious beast with armor your have to destroy before it takes damage.
In general a bit more variety in enemies would be nice. ME1-3 it was mostly just geth, reaper and humans but the environment of planets were always tame (no man-eating plants or something).
Those are things i would really like to see... oh, and put a little more Effort into the romances. Since ME1 they all felt too much like "Do you wanna date: yes, No, Maybe?"... and after this tame love-cutscene nothing ever happened - no love-quarrels or something. It almost felt like a one-night-stand and not a relationship.