The kb/m interface is a bit tedious, since we all got used to using the mouse to move without WASD in the first 2 games. But it's not completely unmanageable, as proven by the many players who have logged over 100 hours with kb/m. My biggest gripe with the control scheme is that stupid search button. I'd rather hold TAB and see items and use the search key solely for finding the hidden items. I'm also not a huge fan of the tactical camera. It's a pain in the rear and I would like to be able to play with an overhead view like we could in the first 2 games. Still, these things will not stop me from playing the game, but their addition would certainly enhance the experience for me.
Talk about yourself. I exclusively used WASD in the first two games. IMO it is far superior to mouse clicking. Granted, big fights saw me use the mouse clicking for tactical commands, but other than that, when I wanted to move around and fight with my controlled character I used WASD.
I agree that they could have added the tab highlighting or always highlighted options - but that's largely a design choice. Most things are. Too many people are forgetting that games are as much about artistic impression than they are about practical functionality. The developers have their own vision about how the game should look, feel and play. Obviously there are some things that are weird, aren't as functional as we'd like or completely missing - yet, if the Devs want it that way, that's the way it's gonna be.
Sometimes, listening to the customers too much, will result in the creation of a game that loses a good amount it's uniqueness and style. The devs should forget about pleasing everybody and stay closer to their own artistic vision.