i said this earlier in the thread, but my problem with AC wasn't the repetitive gameplay--hell, i love some games that have some damn repetitive gameplay--it's that the reasons i was doing the things i was doing (whether it was picking a pocket or eavesdropping) never seemed to "stick," and the motivation was clearly just a very poor veil for the game structure. wait, who is this guy? why am i picking his pocket? none of this matters; he's just some dude i have to press x behind, because that's what the game wants me to do.
it could be the structure, being so similar each time, played into this. of course if you know what you'll be doing, who is who and why they are important will seem somewhat irrelevant. but it still should be said that repetitive gameplay isn't always so bad if it's well introduced and integrated, and if it's interesting to play.
thankfully all indications are that this problem has been fixed, which is wonderful news.