it's really unfair to base an opinion on the series based off AC1 - the improvements in AC2 based on AC1 feedback is probably the biggest (and best) overhaul in the history of games. I can't think of another game that really fixed SO many problems with their prequel. From there, it gets better - ESPECIALLY in story.
so just hang in there - honestly, drop AC1. I never finished it but I'm a huge fan of the story in the series. AC1 as a whole in the series is completely forgettable - don't let it ruin the series. it's worth playing. The "Revelation" at the end of Revelations makes it all come together in such an amazing way in terms of story. I couldn't imagine playing it through at release and having to wait for AC3 all this time (I got the whole series on a steam sale)