I know I didn't post much in the 2015 thread because of the lack of FTA coverage.
Bringing back refueling might help things improve, but they also need to get rid of the fuel flow limit, otherwise it's pointless. F1 management needs to hand out more money to the teams, and more evenly, so that there can be new teams come into the sport and the low budget teams actually have a chance to stay viable and have something to fight for rather than just being there to make up the numbers, running round a few laps down. But the fact that they are so fast and require do much aero to just stay on the track means that on track overtaking has really taken a back seat to the undercut, which reduces the spectacle. This is where tin top racing does it well. Low down force and tight performance parity means close on track racing.
So they either need to blueprint the engines or open up development (the latter of which will only help the big teams, and make the budget teams struggle even more to make the time cut).