User blog comment:Tails365/Still raging about roles/@comment-99.149.168.197-20130220200443

Another problem with "learning one champion in each role" is that there are bans and opponent picks, so, in order to reliably be able to play someone you're good with in any given role, you have to be good with 3 champions in any given role. Actually, top and jungle can be often done by the same cahracters, so for top and jungle you better have 5 champions ready to go (your jungle can pick you top champ, their jungle, their top, and a ban).

That can equate to 14 champions at best (assuming all your top and jungle picks can do both, you can slide with just 5 for two "lanes") that you have to be well practiced with and have proper masteries and rune pages. That's a hell of a lot of effort.