I love this game
I had a pretty bad day yesterday, stuff just didn't go as I wanted to.
So I turned on my Xbox, popped in AC1 and just started playing. Used the memory block replay option for a change and just went to go kill Abu'l. Over the course of the ~2 hours I played, I got totally relaxed. I only did three investigations, but I spent a good 1.5 hours just walking around in the city. I desynced two times and botched the Abu'l assassination pretty badly (ended up falling off the balcony and had to chase him down), but somehow I felt perfectly fine with that. I was prepared for the latter to happen and had explored the palace a bit beforehand. Abu'l's escape route was exactly the same as the one I had planned so I could cut him off.
I fucking love this game. It is amazing. I only wish they'd made more like this.
So you're in an excellent state of mind for speedrunning. That's the kind of feeling it needs.
Edit : my feeling was the same about AC2 in september/october 2010.
I'll probably the project back up soon. 
I know almost exactly how you feel. I hate to admit it, but a little while ago I went back on AC1 to investigate something. Not that I was completely bored with AC3, it's just that the games have changed so much they barely feel like they should be in the same series. I don't think any of the AC games are bad. AC1 feels so well designed, and just as enjoyable as ever. Well, back to AC3, I've got a ton of side missons to do.
Yeah I actually cant wait to replay this game again. What im going to do is replay the series again with mini map off and research the actual events for each game as I go along.