pdb1: As far as mixing it up for us players . There is already the Custom Courses feature in CC's . A CC can have I think up to 10 custom-made , created courses to play at one time . Not new but created to play much differently than the official courses . I think that is as close as we are going to get .
The OP did say (a year ago) that he was talking about entirely new courses, not "mix and match holes".
It's true that the custom course feature offers the chance to introduce a little more variety, but with a strictly limited number of courses to draw from even the different custom courses start to feel similar and without individual character after a while.
More courses will always be welcome in WGT, I think nearly all players are likely to agree with that. But personally I think that adding user-created fantasy ones (even if that became possible) would be a bad move. WGT have enough trouble just managing the ones they have, but can you imagine how glitchy and uneven the experience would be* if there were dozens, or hundreds, or even thousands of user-created ones introduced?
* Yes I know it has always drawn complaints about being glitchy and uneven.