Perhaps it's time to consolidate the forums into fewer but larger. In times past, it wouldn't have made sense to do so because of the amount of traffic -- I don't think that is the case any longer.
If it were me changing it, I would have Verizon, AT&T, Sprint, T-Mobile, Tracfone, and US Cellular forums with all of the pre-paids below their parent companies. In addition, I'd add Ting, Smart Talk, and the other new upstarts.
I think a mild makeover such as that would spark new interest in this site.