Yeah, Tales isn't as good as The Yes Album, Fragile, CTTE or Relayer. Of the 4 songs the only one I don't like that much is The Ancient which keeps Tales from achieving the consistancy of their 4 better albums, it has some fine moments but it does seem random and slapped together, things don't flow together like they do on the other tracks.
And yes, the other 3 tracks are excellent, I don't find them boring at all despite their length, they're not quite as classic as other Yes epics like Close to the Edge or The Gates of Delirium but they're close enough.
The drum part from Ritual does remind me of Can but Trace I think Aumgn is the song you're thinking of. IMO Yes pull off the idea much more successfully. I will never understand why Tales is so criticized for being excessive and not Tago Mago, an album that didn't need to be a double album
at all.
With Tales, if Yes made it today the album could have just had the 3 great tracks but back then you couldn't release a 3 side LP, how would that work?