For awhile I was pretty firm in wanting a spec class of 19T for 4wd buggy as seeing guys running stock and trying it myself just sucked. the stock motors at the time would burn up way too easily in 4wd since they were really RPM based, other than the old orion chrome motor which was torque monster. When I started racing in CT 4wd buggy I was running a 19T Quad Mag, worked well. I still think for a motor spec'd class, 19T is a good match for 4wd buggy.
I however can see the benefits of a spec class as well as doing a sportsman class and right now I am leaning towards a sportsman versus pro setup than doing spec. Mainly because the spec class's like stock are not something that a newbie can get started in as a newbie class.
Having a designated sportsman class versus pro will seperate people by what I think matters, skill level. You also eliminate the issue of who has what to run with who.
Ultimately, I think there are benefits to both ideas.