1. Ringo's loose thudding style brings the sound of the other 3 members full circle and makes the band complete. no other drummer couldve played for them.
2. the beatles are the prime example that music is so much more than silly technicality, and there's a trademarked expression in ringo's style. his drum beats sound like Ringo Starr, which not a whole lot of drummers can say.
3. he did what served the song best. a lot of drummers can't handle taking the backseat to the song itself, even more of them just simply don't know how to do it.
4. his fills propel the songs in only the most appropriate ways. i.e. the way his rolls in Yer Blues make the song sound like it's dragging on the floor, or how he gives the rhythm of Maxwells Silver Hammer that extra bounce.
5. he knows how to make a full atmosphere to back a track out of simple percussion. listen to Come Together. a little flare on the hi hat, and a floor tom roll into the thudding floor pedal rhythm, now through this subtle buildup it pushes the outburst of the chorus into that great territory that blows your mind.
yeah, he's no Ginger Baker, but the man deserves just as much credit for The Beatles sound as everyone else in the band, including George Martin, Brian Epstein, Billy Preston, and Phil Spector in their respective ways in their times with the group.