The function of rollback in every single wiki (as well as those beyond Wikia) is to give users the ability to simply revert edits. There is never a "set" amount of rollbacks, meaning there is no maximum or minimum number we need. Not granting rollback simply due to the fact that "there is too many already" is not smart since it's seen as a "tool" to help users edit easier. It's like a passport - you can obtain one to make travelling easier and the government doesn't just stop handing them out solely due to the fact that there are too many passport holders. Get what I mean? Also, mass removing rollback rights due to inactivity is bad wiki practice as once a user has received a permission status and has not done anything to get it removed does not mean you can take it away. The user can always return to edit. Being inactive does not signify for a bureaucrat to remove rights. They don't do this at the bigger wikis or Wikipedia, as bigger wikis follow good wiki practice. I know you don't like "copying others", but this is simply good wiki practice and BTP should follow it to uphold professionalism. You may argue what you want, but please do consider my advice as I just want this place to grow even further than it is now. I'm not trying to be argumentive. :)
The moderator group was created by Wikia and implemented by them with an update to the forum system. As for rollback, we now have a set number for all positions, taking into account activity on the wiki and a few other things. If activity increases, so will those numbers. If it doesn't, they will remain the same. Direct all your complaints to the CotG.