Another good reason to go 4wd in 1/10 scale is that the cars would be more compatible with tracks that 1/10 electrics run on. There are many places in the US that don't have tracks that are large enough to run 1/8 buggies and 1/10 nitro trucks don't put the power down well enough to clear jumps that were designed for electric buggies and trucks.
I appreciated the purist aspects of 2wd 1/10 truck racing but it's simply dying. Newbies don't want to learn to drive properly, they want to race right now. It's kind of like the offroad nitro equivalent to 1/12 electric. There are small cells of folks who love it but it is just not beginner friendly.