Coming to the end of my playthrough, which was my first as I never played this one when it first came out, I did feel like I enjoyed the game well enough.
I think you cannot go into this game expecting Assassin's Creed II. The jump from one to two is not in any way mirrored in 2 to 3.
The intro to me was long, especially knowing where it went, due to the game being over a decade old by the time I played it, so i can't comment on whether or not it would have felt the same in 2012.

Connor might not be the most enigmatic or engaging protagonist but the AC combat system does lend itself well to his Tomahawk and Knife fighting style.
Some quirky side characters and story pieces that do actually ask to to take the time to consider their greater meaning. This is of course optional.

Then there's the modern day bit. The whole reason we are even seeing Connor's life at all. And honestly. I don't particularly care about this. I full understand that it is the throughline that takes us from one setting to the other, but the appeal of Assassin's Creed has never been what happens outside of the Animus. That being said, even from a place of indifference, Desmond's end felt more than a little anticlimatic.

The crafting becomes more or less inconsequential, while to some it might be seen as a bonus that you can use the same weapon from start to finish, i'd have liked to have some variety. Convoys also felt wholly irrelevant. The result is a game you can more or less burst through in a short sitting, which as stated above is fine for the most-part especially you are eager to get it done. But to me I had to take a little time to work out what the point of the trade system was. As it goes, not much.

Edit: I actually came back and edited the score down after playing the DLC. See my review of that for why.