DREDIOCK:
My SWAG on the reasons:
1 - Chasing whiners is about as foolish a plan as I've heard. You can't please everyone and whiners like to whine. They'll just find new reasons to whine;
2 - I can't imagine someone being at all pleased about spending 100 hours or so building a terrain for AH just to have HTC give it away to someone else to change things around on it. This would be a great way for HTC to kill off the terrain building community in the game; and,
3 - Even if HT disagrees with my first two reasons, anyone claiming they can take someone else's work and make it "better", without first having put the effort into proving they have the talent and skills to do it by building a universally popular terrain, isn't exactly building anyone else's confidence in their abilities to get the job done properly.
Here's an idea:
Build a terrain you like and submit it to HTC. If you do it well and HT accepts your work, you'll have a terrain you like to play on.
Cheers,