Yeah, for once, I'm not trolling Moyes. I just think different people see different qualities in the same player. Thiago has the technique down, but he is known to have a brain fart here and there, and a misplaced pass can be doom for a top team, since opponents will often set up to counter and pounce at the right moment. As an aside, this is one reason I'm not too dismayed about losing Suarez, should it happen - he gives away possession more than anyone else in the PL, and has a sub-80% pass rate.
Bayern's setup has more security, with Gustavo, Martinez or Schweini offering horizontal movement and protection. Alaba and Lahm also come in more narrowly to press than Evra and Rafael. United doesn't play with holding midfielders, and neither Cleverley nor Carrick are much in the destroyer mold.
Therefore, I could see why even at 20-odd million, Thiago could be seen as an unsafe choice to a United manager. He'd fit in more, stylistically, at Spurs, Liverpool, Arsenal, Chelsea, or Swansea.