They'd definitely get chewed up more because you'll have a jet that is faster than the jet we currently have and one that is able to perform excellently at the high altitudes the B-29 routinely flew, not to mention more hitting power. The MiG would have a far easier time intercepting and engaging B-29s at high altitudes in game, without any of the negatives that currently holds back the ME 262. It would be "Black Tuesday" all over again.
ack-ack
But you have to take into account the fact that those mig15'ers were trained pilots who had their aim and flying abilities fine-tuned before ever being given their wings.
In AH, the majority of its numbers are casual players, Who arent in a squad that practice Gunnery or ACM's. I personally find Gunning from a stationary platform(Buff guns) is easier than gunning from a manuevering aircraft.
Sure, there would be a few skilled jet pilots who could shoot the buffs down with ease. But the majority of the group would consist of 2-weeker-level of skill's pilots zooming around in Jets. They'll prob look at the mig15's armaments, and think its safe to dead 6 the b29s, etc,etc.