Either you have debates or you don’t, you don’t have them if you try to do it with 25 or 30 people, some think even more may run in the GOP.
The GOP is getting a lot of people like Santorum and Ben Carson who have no political futures, the GOP has to figure out some way to deal with this trend of people merely looking for publicity for their non-political aspirations as they seek work.
You exaggerate with the 25 or 30 people. It might take 2 or more debates but all should get equal TV time early on. Later it may make more sense to pare it down. Now you will push away lots of voters as you push away the candidates.
I’m not saying it won’t be challenging. Imagine back when candidates had to literally “stump” in each location by riding a horse and having their audience travel into town.
In the age of technology this should be no big deal.