you can still do a lot of QoL upgrades like gui and lights and improved centerprint/bottomprint restrictions. theres a lot to improve that doesnt require clients to have the custom client as well. by the time the only improvements are those left, ideally the community update is already very widely adopted and it wouldnt be a stretch to require it.
This would be a better way to go about it. Start with simple stuff, like bugfixes and QOL updates, nothing too big. Add the bugfixes that would only be possible through dlls and stuff, Then, if its REALLY needed or if the community would be accepting of it, start adding the big stuff.
Modding is really big for this game and the intention of this should be to fix default bugs and add QoL additions that wouldnt be possible without dlls and stuff. Expand and remove limitations on the torquescript language and add a framework to make add-ons created with lua or javascript possible/easier. (if it isnt already with those dlls)
The focus of this shouldnt be to make the game look cooler, it should add the frameworks to make it possible with normal add-ons.