Henry,
I doubt that the career curve is specific to a player in the sense that each player is desined to a career mode. (eg. player A has a career mode of "peak-early") If you backup the league at the time point and repeatively run the league for a specific time frame, then you can see all sort of player development. Player A who received a talent drop in run no.1 can possibly receive a a talent increase in run no.2. However, the thing is that player A could perform bad in run no.1 so that he *deserved* a drop and vice versa in run no.2. So, that way, player development is influenced by performance (which is actually mentioned in OOTP6 feature list).
Or, the development is just a random chaos that you will never know how the player turns out even with good/bad performance. However, I do think the first case is more logical. Though if the first model is true then maybe we need to worry about the result long-term slump due to player being *unlucky* in a long period of time. So, this way, the player's development won't be *punished* by luck.
Either way, as long as the career curves of all players prove to be realistic then it doesn't really matter on how development is actually implemented.
