I might be wrong, but the first ones that come to mind when precision and clarity are the topic I would have to say:
1- Josef Hoffman
2-Rachmaninoff
3-Ashkenazy
5-Michelangeli
6-Rubinstein (same case as Angerich)
I also have to agree with MattL, I once heard Luganski's recordings of Chopin Etudes, and I saw combined precision and clarity, and a very good example of Rachmaninoff's technical precision and clarity is probably shown in his recording of Handel's Blacksmith suite, the way he arranged the polyphony was prodigious.
But those are only my personal opinions.
Mario