First off, the whole dying thing just annoys me. For one, it's been done -- and better -- in Spider-Girl; even his appearance in Spider-Man: Reign had more oomph than this. For another thing, the last time we saw Ock -- back in the Thunderbolts, before Steve Rogers died -- he was in perfect health!
The story felt rushed and short. Maybe if it was a 5-issue arc or took up all the pages of #600, I'd have time to get used to this new development... not to mention have more Ock-time as, for example, "Web of Death" during the Clone Saga.
I'm willing to buy him trying to do something good as a legacy; Ock has always been an egotist and a narcissist above all, and turning NYC into a smart city based on his design is nicely grand. But I don't like how it IMMEDIATELY goes pear-shaped, and I honestly hated that Spidey's brainpower outdid Ock's.
Otto is not a machine; his powers may be his brain and his tentacles, but the main thing I like about him is that he's a man as well. Physically ordinary, even average when you consider that most Americans are overweight.
And while there's a definite TO BE CONTINUED feel at the end, my pessimism tells me we'll be waiting another couple of years before we see Ock again. :P OK, maybe not that long.
In summary, I just felt it wasn't worth the wait.
Pluses: the banter was good ("Spidey goes to first base with Doc Ock" made me laugh out loud) and of course the return of Mary Jane makes me go YAY!
Basically, I liked everything EXCEPT the Doc Ock stuff.
So, meh.