This will sound trite, but I'm completely serious. The number one thing I want to see in the next MacBook Pro is the abandonment of the Touch Bar. Make it a row on the keyboard again.
I didn't think that the Touch Bar was useful when I first saw it, and now, six months later, I haven't found one more reason that I'd want ever want it. I don't want haptic feedback or any other kind of improvement. Apple made a mistake and should own up to it. Just throw it out.
Aside from that, I'd love to see a little better battery life and would have no problem whatsoever trading away a few more millimeters of thinness if I could get it. The MBP is thinner than I need already.