rahal: The UI is just different. BW has tool tips (done right) etc and other modern ui conventions, genesis is old school.
The UI is not "just different", the UI is a big step backwards.
It was much worse before beta testers complained. I hope it will improve via patching.
Lassitude: You are paying $20 for new (but not good) graphics, a worse UI, and a whole array of serious bugs and issues which will make you have to repeatedly redo battles, exit and reload the game, or crash out of the game abruptly. Nothing new to the actual gameplay has been added. It is simply a graphics, UI, and inadvertently, bugs update to Genesis.
The campaign has actually been made significantly faster to play through. In genesis about 3 out of 4 battles did nothing to advance the plot, instead just being random conquest.
Also genesis forced you into ironman mode (only one save and it was auto deleted if you lost), MOTBW lets you have many saves you can revert to
There are also some new features like "type shards" (world of rust, world of crystal, etc)
Also, while the new engine added some bugs, it is far more playable than genesis which required you to downclock your CPU to even play
For all its warts, MOTBW is the clear choice