It would be great to have pixel bit depth editable on a per comp basis rather than a global project-wide preference. This would be similar to the preference to appoint different 3D renderers and color spaces to comps.
Another +1000^1000 upvote! So often I'm working in an 8BPP project and a single element / effect introduces banding... whelp. 16BPP here we come. Sure hope there wasn't a deadline looming!