Sorry I don't have time to read most of the other replies, but I wanted to chime in and say that this idea is actually more realistic than the warrior thing. Strong warriors don'tr save the world because you can't normally save the world by punching someone in the face.
No, the world is saved by engineers. Challenges are met when engineers can design power plants, water filtration systems, modes of transport.
You can start out in a poor village. Most RPGs would have you fighting rats, but a poor village wouldn't really have killer rats -- it would have problems keeping enough electricity going. It would have problems getting water. You as a "craft person" could solve those problems. Then when you've seriously improved the lives of that village, someone in a bigger city hears about you and you go there to help solve those problems. You don't kill trogs for loot, you build useful things in exchange for money or other items.
Makes perfect sense to me, and it could be just as epic as any "punch the bad guy in the face" scenario.
1) A post count limit, so only people who have participated in the forums a bit can post new threads in that forum. That may cut down on the kids with stars in their eyes.
2) A very small, token amount of money for posting in it. Maybe just optionally, so there are "premium" and free. I'm talking about like a dollar--not a serious barrier to any adult with even the slightest bit of commitment, but enough to weed out the sorry cases.
3) Limit the "bumping" ability somehow. Make it impossible to double post in a thread, so you can only "bump" a thread that has a reply.
We could do any combination of those 3 things and I think it would help.
Yeah, I had a couple computers before there was such a thing as a hard drive in a home computer. You had whatever floppy, and the working memory, that's all. Oh, and the floppies were definitely NOT 3.5".