No - probably will have to compromise with the design, plus the one in the current iPhones is fine. I'd take a mm thinner over a removerable battery any day.
Removable battery or not? I say yes because I feel like the lifespan of the battery will last so much longer if it was removable.
I've had mobile phones for nearly 20 years. Most have had removable batteries. I've never, ever swapped a battery. Ever. Only time I see the battery is when I drop the phone and the stupid door flings off and the battery ends up on the floor. Can't happen with the iPhone.
Removable battery would be a massive negative for me.