I wrote a guide in another topic to enjoying AC3:
I find if you focus on the following things, you'll enjoy it more ->
Allow yourself to soak in the atmosphere of the frontier. Go hunting, completely off the grid. Really try to see how long you can streak tree exploration. Cause some problems by hanging people from branches (this can be REALLY inappropriate sometimes, though). Because the framerate is least bad in the Frontier, there is a lot to enjoy. The atmosphere is unparalleled. When the weather starts in (no matter whether you're in a city or the Frontier), is is mouth opening.
Really soak in the NAVAL BATTLES. This is probably the best additive, non-essential gameplay addition to any open world game. It is astoundingly good, and I would pay $60 for an expanded version of the concept.
Ignore Connor. He is dumb.
Try to really get into the side missions, which are often quaint affairs with fun little diversionary aspects. Building up Homestead can be rewarding, even if the ultimate rewards are comparatively quite tiny.
Try to read most of the Animus entries. They can be quite clever and often overcome the generally terrible, disjointed writing of the primary story. Apart from some of these being pulled directly from period newspapers or Almanacs or whatever, they often have funny little quips by the British dude who is bitter about America's victory
Do Peg Legs Trinket quest. Really fun little missions equivalent to the "challenge tombs" of past games.
There are many more, but the game isn't BAD. To me, it's like the way AC1 was in terms of foundation... you can just tell a sequel built from this will be great. But I think it is definitely better than AC1, at least, significantly so (except the assassin missions are inferior, as always. Why did Ubisoft tone this aspect down in the series?).