No doubt he’s well-organised, a good analyst and a clear communicator. That’s great in providing juniors and sub-elite players with an environment to improve their stroke mechanics and general level. That’s actually his job and it appears he’s quite good at it.
I’m not here to blow holes in the guy because, as you say, he’s closer to the solutions than a lot of American-style coaches focused on producing serve+1’ers. But there’s more to producing top players than what Pat offers. And he hasn’t actually produced any of those players. There’s a psychological element to producing the problem-solving, tactical flexibility and absolutely bottomless pit of self-belief to convert top-20 talents to become top players that intimidate the tour and win consistently. It doesn’t look like Pat has that skill, and that’s putting it very mildly, given Serena’s problems facing the final hurdles.
No way in hell I’d let him near the control panel of a player like Med. Med has hauled himself to #2 in the rankings by talent, IQ and sheer force of will, all with technique and movement that can best be described as unlikely. Med either maxes out what he has now, with a psychological-observer type like Gilles or goes into the wilderness for a season or two, does a full technique rebuild with a guy like Patrick, assisted by a psyche-rebuild by Gilles or other, then comes back a different player.