Why isn't Assassin's Creed 3 as fun as I remember the previous games being?
+ New take on the economics of a "homestead"
+ Novel ship-based quests
+ Killing animals is a surprisingly fun diversion
What didn't work:
- 2-Dimensional plot line was not at all engaging
- Economics of the homestead
Why isn't this game as fun as AC2 (in my opinion the best in the series)?
In short: immersion matters with a game like this. If the story is weak you are immediately in dangerous territory as a developer, because all of a sudden I don't feel like playing the game the way you envisioned it; instead of sneaking and stabbing, I'd rather just accept partial completion barging in and killing everything because I don't care how the characters will respond (if they in fact respond at all). The predictable twists and stale dialogue absolutely failed to make me feel that I was part of the American Revolution, so that I thought the mountain-man quests were more interesting to complete than the main quest.
You might notice that the "economics" feature of the game is mentioned as being both good and bad. Here's why: the previous games failed to bring the feeling that you were really adding value to your craftsmen, simply paying for upgrades or killing templars didn't feel like it should translate to more gold. This game has you getting raw materials and causing your peons to forge it into something with more value, which can then be sold. It should work, but in reality there are less tedious ways to get money in-game, like merely playing the main quests so this feels like an obnoxious add-on instead of an improvement to the money-making mechanism of the games.
Another seemingly good idea to fall flat were the ship quests (good reason to be leery of AC4). It turns out that one of the best things about this series is the involvement of a third dimension, sneaking in over rooftops or through tunnels. Once you board that ship, all you have is a clunky tank in which to play missions that all feel like, well, the same mission with more or fewer enemies. Ubisoft should have taken a page from the antique "Sid Meyer's Pirates!" rather than copy their own, extremely annoying Leonardo's tank battle from AC:Brotherhood.
In short, the "improvements" to the series haven't actually made it better, and I have found that as far as replay goes, I'd rather play AC2.