Typical white guy - can't feel the groove?
He has to be 'rigid' (especially in something like Levee) otherwise it becomes a sloppy mess. It's called being locked in. He is a very good drummer in that he can be wild and crazy (lets say Moonish) but has the tact to not do that all the time. ... though that tact was often tossed out the window when it came to the length of his drum solos ... and not that I'm knocking Moon, he's a big influence; different things work in different situations and Zep was definitely sludgier, so a free(er)-form Moonishness wouldn't have worked as well.
It's a taste thing also for sure - I am very old school (like caveman) in that I have no issue with repetitive parts throughout a song (this comes through in my bass playing as well) as long as it is a good groove that a lead part can dance around nicely. It's kind of a primal trance meditative thing.
I like Bonham for many of the same reasons I like other drummers - Yuval Gabay (Soul Coughing) for example. Other fave drummers include Moon as mentioned, Topper Headon (more up your alley... except when he wasn't; Crooked Beat and jazzy moments etc) and Fuzz Townshend.... note specifically the distinct lack of Neil Pert; busy in a bad way IMHO - technically very skilled, but he's a chronic on the beat over-player; mathematical/geometric vs organic. I would consider that sort of thing undesirable even when it comes to guitar playing (with Keif being a prime example of how awesome sloppy guitar parts can be). I guess, as a drummer, I am very in tune with where the beat is, and 50 years of pop music has really hammered home 4/4 and I am not interested in anything that is too on the nose about it, as if we couldn't figure it out otherwise. Also his kit (Pert's 30 piece monstrosity) makes me want to puke (though his Signature line of cymbals by Sabian is very good, especially the hihats).
I don't mind the Deep Purple dude, but his style is not particularly distinct; pretty straight up drumming. I suppose from the perspective of other band members this is a good thing (I myself have been asked by guitards to play more on the beat occasionally - they're so easy to confuse - this song is one example where the guitarist had a hard time but understood that the drum part was a big part of the song and didn't ask me to change it, so much as to help him work through it and figure it out: http://grannygremlin.com/PTV/LonelyBoyMotel/PTV-2-BirdsNest.mp3 ... not particularly behind the beat, but the accents/stress are not always on 1 and 3).
Paice, post Purple, has more style (even jazzy in some bits, and not on the beat), but he's still too rigidly mathematical for my tastes, and just playing a very boring straight up 4/4 for much of that song. ... then again, so is his lead guitarist there, that's the sort of thing it is; you can't just do what you want, it was to work as a whole. To me, messing with the accents, playing behind the beat etc, is a way of making the drums more interesting (contributing to the song more; becoming almost a melodic element) vs just keeping time (which frankly, each musician in the band should not need the drummer to do for them.... but I have played with many a guitard that needed this human metronome). I also like cut or double time vs the rest of the song as another way of contributing musically (Ministry did this a lot, it's kind of a typical way to get that hypnotic feeling).
... so yeah, sometimes I like to drag, it's not a sign of error, but an artistic decision and it's fair to like or not like it as such. Despite my ragging on being overly mathematical, I can appreciate that sort of thing as well, but again, mostly when it's taken to the next level (no offense, but the 70s was a long time ago, and that stuff no longer really excites me; bacjk then it was new and refreshing if a drummer broke out of the 4/4 and did a fill that lasted longer than half a bar) - a prime example is Mathrock monsters Battles (but that gets in to odd time signatures, atonality and other things generally relegated to jazz, but it's the only kind of acute beatiness I actually like):