After watching a few game play videos, I am actually looking forward to buying this game (once it has been out for a while and I don't have to pay $60 for it... no thanks Ubisoft) because it looks good fun.
Evie looks like a good character, and I think her seriousness works as a good antithesis to Jacob who seems to be a bit like comic relief sometimes.
The game looks a bit silly (Charles Darwin getting assassins to go after his scientific opponents???) but it looks interesting and fun enough that I don't really need it to be hyper realistic or serious. Sometimes games are just fun without needing a great story.
That said I've never played an Assassin's Creed game before, so I'm probably going to give AC4 or AC2 a try before I decide whether I'm going to get this one.
Like I posted in another thread, AC4 is definitely fun. But AC2 and 4 are really really different. AC4 took a really big turn away from the series's roots, with the main protagonist being a pirate after gold and social stealth not being a big part of the game. AC2 is the best in the series, that's the game that will show you what Assassin's Creed is really about, since it is focused on an Assassin. The graphics might be a little old by now, but the overall atmosphere of the cities like Venice, will make you forget all about that. This game is a tremendous amount of fun, with social stealth, challenging combat (more than anything after ACR anyway). I would say that for people who are new to the series, or just want to get a good taste of the "real" assassin feel, then AC2 is definitely the place to start. And Ezio's character is just plain awesome haha.