I'm in favor of the cost cap, but there are some downsides;
- It's an extra opportunity for cheating - if there's no rule, you can't break it.
- I see more instances of only one driver getting the new upgrades, to be evaluated and eventually produced for the 2nd driver if it's deemed worthy.
- Unfairness; If I crash into you, we both have damage and both suffer the cost consequences (or Las Vegas vs Ferrari)
- Teams might choose to spend their budget for next years car sooner, if they think this year might be a bust. For instance Ferrari and Red Bull this year might want to give up already.
I think these are all fair points.
1) is true, but probably easier to police than thought (or at least I thought). Sure, they can try to get away with stuff, but to sway the bar you would need HUGE stuff, and you can't hide that.
2) i don't think that's new. Red Bull with Webber and Vettel front wing saga - if unlimited budget (or huge budget), they will do 11 iterations instead of 1, but the last one will still be budget (and time) limited.
The more concerning for me is around car direction. It makes sense to prioritize feedback and invest in 1 driver only, especially under a budget cut.
3) here it could be tweaked - you are right, it is unfair. It could be that the guilty team covers some sort of costs, or you give an allowance in the budget for rebuilding your car if you were 100% innocent. It doesn't have to be over engineered, some sort of generic money to cover some of the costs
4) this was always the case. Maybe the benefits are larger, but i think there is a deadline anyway on how early you can start