You can vote on league rules community-wide for iGP Leagues here:
https://igpmanager.com/app/p=community
The reason we've gone down this route is we had to make a decision about the future of the game, to make it sustainable to run it. The more customisation we were offering the more fragmented the communtiy became. We also wanted to offer more customisation, not less, but delivering that for those that wanted it was contracting the community into ever smaller pockets where yes, some leagues had highly bespoke setups that worked for them, but new players joining the game had a hard time finding something for them.
In January, I will be working on a realistic car setups system, Classic mode (2D only) and Offline mode leagues. These features could not have been justified under the old system, they would have only split the community up more. Now, it can be justified to spend time on all these features as they become perks you can unlock and ways for us to sustain development.