I played them all and I haven't found one thing to call stupid, well, if you dive off a short range toward a little, tiny cliff, his body hangs like he's dead, but that doesn't matter xD
For story, it is very original and sometimes, things feel like they repeated themselves, but I don't think I ever felt like it got boring or anything. The acting was great too, and the graphics were pretty great (beautiful if you own a PS3!), interaction was nice, gameplay was nice and even character development.
Overall, it is a great series. I hope this isn't the last AC game...Those cliffhangers are really good >_>
AC sure is good at those cliffhangers. I wonder what Brotherhood's ending will lead to in the next game.