If I may say my dream game would be almost like a marriage between the characters from a Mass Effect 2 game and take the controls and combat from Transformers War for Cybertron.
WfC was a great game. However, it was really true to the source material and naturally being based on the transformers cartoon's from the 80's it was gloriously cheesy.
I prefer to move away from kiddy stories and go for a mature rated game that has adults, not kids for fighter pilots. People with real problems and flaws (what do you do with a fellow fighter pilot when you find out their doing heroine on their down time?).
But the thing is War for Cyberton controlled well and mixed robot and flying really well. The multiplayer in WfC was top notch and my brother and I played it quite a lot on our X-box 360's. I don't think you need to reinvent the wheel, so just copy WfC.
Of course Mass Effect 2 is a great game in pretty much every way. But if I had to pick out a detail of that game it would be the characters that are probably the strongest aspect. I was more interested in what everyone was doing on my ship and wanting to have conversations with them to learn more details about their lives. Combat was just an average cover shooter that was usually not too difficult. ME2 was actually a pretty linear game for fighting, although so was WfC, or most games for that matter.
So if I could make a game about being a pilot of a transformable fighter/robot I would do it that way. Start with a brewing war that sucks in the main character you create, place the main location on a warship, get your brief, have a battle, then spend some down time to wander the ship and talk to the other pilots and crewmen, recruiting new guys and gals as you go through the game. Then a final battle with all the cards on the table where anybody can die, including the romantic lead character you've picked out for the hero.
One thing I actually don't like about ME-2 was the fact you can have a perfect run, and have everyone survive. No, I prefer the ME-1 or Witcher game style where you come to a few points in the game that forces a decision on you, and no matter what you will have some good, and some bad things happen. You just have to pick the one that is terrible a bit less than the other one that was more terrible and live with what happens.
That will never happen of course, but I can dream.
Hell, I was even hoping to see a transformable Cyclone motorcyle/power armor get added to Halo. That would keep me happy.