Revan was knocked out by the blast from Malaks ship, but he never suffered from amnesia. He was brain washed by the Jedi Council to fit a new identity, one that would serve the Council. To me, that makes it quite a bit more interesting than "ops, knocked in the head and forgot everything".
Also, it was never done to reset levels or anything like that. There's nothing in KotOR preventing a perfectly normal start, as a standard person with a standard past, and then become a Jedi. It's done as a vital part of the storyline, to create the twist about 2/3 into the game (a very good twist, I might add, one that made my jaw drop - "the main character is WHO?!?").
And another thing - they've never done anything similar before or after, and with only one such story, I find it very hard to believe that you happen to see a pattern. It's impossible for anyone to see patterns where there's only one variable (i.e what's the next in line: 1... ).
The "Aribeth character" will probably be present though, as this (unlike the memory loss thing) is definetly a pattern.