Today I picked up my 812ce from the local authorized Taylor tech, who did a fine job for me. There really wasn't anything wrong with it, but I kinda thought the action was a little high, just subjectively, and he confirmed that it was above spec. He made a slight adjustment to the bridge and now the action is exactly on spec as far as height goes. The new strings are the .012 Elixirs which are the size Taylor specs for the 812. It had shipped with .013s. He tweaked the truss rod accordingly, and in response to my question, said the guitar doesn't need a "bow" in it. It was flat to begin with and we left it that way, which I prefer. I don't play with a hard attack anyway.
He said he could set the action lower if I want, with a neck reset, but I'm going to play it the way it is now set up for a good while before I think about anything further.
Anyway, now the action is noticeably improved and it was very good to start with. The .012s feel just a little softer to me, which I like, but the great tone is no different as far as I can tell, although I haven't run it through an amp yet.
I think that anyone who has played for awhile can feel and notice what seem like tiny aspects of an instrument's dimensions, neck shape, ergonomics, set up, shape, etc. I think that's probably true of all musical instruments.
The work was covered under Taylor's warranty, but I would have paid for it anyway. Very competent, knowledgeable fellow.