The Banshee is one thing I'm curious to how they'll balance. For one, ditch the fuel rod blast. It has no business in MP, whatever if they feel like using it for campaign. Make the plasma cannons on the Banshee useful and it'll be a decent aerial assault.
Spawns will be no different than any other Halo (bad), so I don't think that will change a whole lot. Map size and instant spawns will alter these changes, as well.
Just think if they leave the Banshee alone (which I doubt they did) and yet combine that with instant spawning... It would be a whole new level of spawn killing mayhem.
As has been said before the Banshee really needs to cut all the bullshit aerial flipping. Allow it to do a single roll or backflip (to avoid rockets), but then give it a full cooldown period of 10-15 seconds. Yes it should be powerful and a skilled pilot should still be able to get 4-5 kills at a time. But the way the game works now it can be near impossible to hit it with anything other than a sniper.