Honestly I think narrower cars would make a huge difference (and of course they went and widened them this year... SMH). Passing almost exclusively happens on the straights, unless you're Max Verstappen who is singlehandedly keeping races exciting (maybe some Vettel / Ricciardo in there).
Make the cars narrow enough that passing in the corners is feasible and I think it'd make a big difference.
Yeah, it's to where the only exciting races are the wet races. I've only been following F1 for about 3 years now, and Brazil 2016 was hands down the most exciting race I've ever seen.
The challenge is to find a decent set of regulations that allow decent downforce and fast cars, without too much wake disturbance.