What's the shortest start/finish straight on the calendar? The only real limit to the number of teams in my mind comes purely from how much longer the cars are that at a certain point the grid has to wrap around the final turn. I don't think we're anywhere near that on any of the current tracks, though.
Is there any particular reason or regulation why the F1 races couldn't use a running start like other categories? Where everyone departs from the pits at fixed intervals and then the race starts after a 0 lap. Is the grid start from standstill mandatory?
Standing starts are almost as integral to the identity of F1 as open wheels are. Right or wrong, F1 is almost certainly never going to switch to rolling starts.
Presumably you'd get less wheel-to-wheel racing, and considering that most recent rule changes have been in pursuit of more of that, it seems unlikely they'd take a course that resulted in less.