Now that someone's listening: I don't mind the 15min Lambda timeout, but it would be great to get rid of the Lambda + API Gateway 30s & ~6MB limits. Those always bite unaware devs in the butt and workarounds for them take quite a bit of effort.
But being real, we hear you on this one. I can't comment on API Gateway's roadmap here but this is something both teams is aware of. The reason it is the way it is today is for a valid reason. But this is def something we hear pretty often.