First of all I'd like to say, superb game. I love the slow pace and tactical gameplay. Initially I was thrown off by it and got slaughtered, but that's because I was trying to drive tanks BF2 style. I agree with the previous posters on the steering issues with Thors and Cutters. My other gripe is a minor one with the scoring system: I don't like how the death of your automated turret counts as a death for you.
However, adding a strafe function to the hovercraft might unbalance them, especially on worlds with similar physics to the ice world. One of my favourite chassis, the Tempest, can already fly rings around tanks and AFVs, as long as I stick to the flats. It's quite easy to charge a Thor at an odd angle, then swing around behind him and ionize his rear.
I personally don't think the Hurricane is too overpowered, remember this is a team game. The reload time on that thing is extremely slow, just get a buddy in a ATGM vehicle and approach from two sides.
Many of the complaints about arty and ATGMs can also be dismissed with a bit of experience and teamplay. If you park your MBT on top of a hill and don't move after every shot, then start charging forward, of course some sneaky Shrike is going to light you up. Try getting some boyos in Hermes to give you an escort. You'll appreciate the immunity to artillery and missiles, they'll appreciate you knocking out tanks.