I think that the future of things is leaning towards 1/8 scale 4wd electric for outdoors on multi use (ie tracks that run various scales on one) tracks. With tracks going to the bigger jump setups, you need something that can handle the rough at places that do double duty.
A 1/8 scale brushless electric setup can do that. And with Castle Creations making a Monster Mamba Max that is looking to come with a Neu motor for $300 estimate right now (usually the Neu's are like $200+ alone), you can have a very nice 1/8 scale conversion setup for a comporable price to a race level fielded nitro 1/8 scale. And you cut out a lot of the common headaches you get with nitro.
I tried nitro several times, and I loved the scale and feel of the vehicles, but working on engines just wasn't my thing. And I was also discouraged about it when you see guys who are highly skilled with nitro also having issues too with tuning or some clutch part let go.
Now with my electric 1/8, I just charge up the pack, plug it in, and go. For fun, once in awhile I'll turn on reverse too
I got into my ride pretty cheap ($600 less charger and receiver, everything else included used), but even if I paid new, it was well worth it.
As for the 1/10 scales, I really like 4wd electric buggy, but I can see the issues that can arise if the track surface is blown out by truggies and the like. When in CT running 1/10 scale buggy, I remember how bad it could get going down a truggy blown out straight. Cars flipping for no reason (from what you could see on the driver's stand) till you got out there and see the huge pot holes that the truggy guys just blew by.
I think that AE releasing the B44 at a very competitive price for a 4wd is a good push, if they can release a cheaper version RTR in the future would go even further, maybe throw in a brushless LRP unit too. Same with Losi, throw in a losi brushless into those XXX-4s and get them moving like they did with the sedan. Doing this will keep the momentum going. heck, pop in some lipos too. Losi's doing it with there 1/18 scales now in one of the configurations.
As for the 1/10 scale 4wd truck thing, I am all for it, but I am not sure still how that will translate against a 1/8 scale electric as far as perceived value, depending on the cost and what you can run with. Seems people are more open to let you run 1/8 scale electric and nitro together (as long as you do your pit stops) than 1/10 scale 4wd truck with a 2wd truck. I am looking at a CRT .5 conversion as a buddy of mine has the nitro version. If he keeps his and runs it in the summer, maybe I'll do one too.