You kidding? If the top three drivers share $19-20m a season, that's a pretty nice bonus, even on top of their salaries. I agree with you about the pit lane walk-through and driver access. I'd even be happy with a cameraman and (hopefully funny) reporter wandering the paddock - inside and outside the motorhomes. Free access. Show us the gee-whiz stuff they hide back there, and get a few off-the-cuff interviews.
I would rather see some kind of heat races on the Friday, not one car on camera at a time doing time trials (I get enough of that on the Sunday at some of the more processional tracks). But honestly, any improvement would be something.
More importantly, I think that Saturday could be improved by having two 20 minute, no refuelling, heat races with the first grid decided by lottery and the second a reverse of the finishing order of the first one. Aggregate the times and you have Sunday's grid. It would be a blast.