The problem is that the teams are always willing to spend whatever they can get their hands on. McLaren, Ferrari, Mercedes and Red Bull are very happy spending 200 million+ pounds a year and no amount of "cost cutting" is ever going to change that. To keep themselves relatively competitive the rest of the grid has to spend themselves into oblivion, or risk being so slow that they can't qualify anyway, also leading to oblivion. The highly restrictive, and increasingly so, rules don't help as it forces the teams into highly expensive development by reiteration. Again, the big teams can and will spend whatever they like on this and we've seen how Red Bull has mastered this and just how complex their aero is. I've said it before and I'll say it again, if we want F1 to be the best it can be then we need to rip the sport up and start again.
First order of business would be to take Bernie, CVC and the rest of the share holder leaches and throw them in a dungeon (preferably Max Moseley's) and throw away the key.
Then there's the obvious redistribution of the sports income. I can't be bothered to work out the percentages but there's no way that one team that's already rich should be able to gain 10 times that of another. I'd still allow the extra "bonus" payments but limit them to teams that have been in the sport in their current guise for 25 years or more (so thats Ferrari, McLaren and Williams, and Sauber in another 3-4 years) and not have them being anywhere near as much as they currently are. The rest would go to the FIA to be spent on running, policing and promoting the sport.
Budget caps. I know this would be extremely problematic to implement and police but I think it's the only solution that will allow F1 to stay being F1 and cut costs. I think the rules would require careful wording forcing the teams to demonstrate that they have spent their budget on developing and building the parts themselves or if something has been outsourced then it is available to all other teams at the same price. Obviously engine development wouldn't be included in the cap as that would kill Ferrari and Mercedes. This might be a little (or a lot) simplistic but I think it's a good direction to start from in making a budget cap realistic and workable.
The tech regs is the difficult part. One thing I would like is to see the sport borrow from the WEC's rules that has allowed for such variety, and go even further. First I'd like to see the teams given the choice of going with current style cars though with the regulations governing where the bodywork can be tightened up in some areas and relaxed in others or go with ground effect cars that have very restrictive upper body work rules. As for engines, going with WEC style energy consumption per lap rather than the max fuel/flow rate rules we currently have and complete freedom on engine configuration would be brilliant, especially if someone like Cosworth, AER, Zytek or Judd can be persuaded to supply a standard turbo or NA car without the need for supper expensive and complex hybrid systems. The idea would be to bring back variety to the grid, I mean who wouldn't want to see Honda racing a Hydrogen fuel cell car against a Ferrari V12?
I don't mind customer cars in themselves so I'd be OK with them being brought back to the sport, preferably with the grid limit removed, allowing customer teams to run just 1 car if the want to and forcing any customer team to make modifications to year old cars themselves, or at least outsourcing the work to any other company that isn't one of the other teams, and that they have to build their own car after a maximum of 5 years in the sport. Energy consumption rules can be adjust to prevent them from being too competitive and forcing out the midfield teams, but it would make for an easier way to get new teams in and up to speed with the sport and then building their own cars.
Maybe it's largely fantasy and has too many problems but I quite like these ideas.