I didn't want to start a controversy. To explain myself a little better, Danny has never been the most even drummer, but the tempos are all over the place on this record. He's very unsteady, changing the tempo almost every mesure in certain passages (especially the climax of the songs). This has nothing to do with the writing (I agree he's the most interesting player on the album), but with the performance. It's disheartening how he drags and kills the mometum at some points. I think he would have played the same parts way better 10 or 15 years ago. He's 58 years old after all.
About Maynard... I understand that he can't scream anymore, but he has lot most of his power in the high range, and I feel he played it safe on Fear Inoculum, even from a creative point of view. To take an example, the prosody is pretty much the same in all the songs (with a breaking of all the phrases in short groups of words), when on Lateralus Maynard was changing it every song. Even his lyrics are nowhere near his best. At this point, I think he doesn't care anymore, and haven't for at least a decade.
Adam has always been the weak point of Tool, and let's be honest, he's a mediocre guitarist. His main skill was writing great riffs, and at this point, he has exhausted all his tools (sorry for the pun). He tried to bring some new stuff here and there on Fear Inoculum, but I can't fathom how the band could think Adam could hold long instrumental passages on his own. Yet, I've nothing to say about his performance, it's pretty much the same as the old days.
I might seem overly critical, but I think the album is fine, and better that I thought it would be after 13 years. It's just that they're getting old, and it shows, and that metal have changed a lot since 2006, and there is better stuff out there these days.