I understand where you're coming from. I guess it depends on where Blizard as a company want to take the game.
Are their main options:
A - Take their existaing considerable customer base, and build on what they want / need / demand / use ie keep teh game essesntially the same just upgrade it. This will keep the high retention of their existign fans but end up with a game that will probably only score 7/10 in reviews hence be overlooked by some new players.
B - Build soemthi new from the Diablo Concept (hence my KotOR remark) which will be more appealing to newer players but less so to the older ones. After all, look what iD have done with doom after a few years of "doing other stuff". Should Doom3 have been al Linedefs* and 2d Bitmap enemies ?It would be feasable to even provide a free D2 expansion of the content stuff from 3 ... Ok, that is a dumb idea but shows what could be done with a bit of imagination.
...
oh, there is also C - **** it up totally alienating old and new fans alike.
Personally i'd say they need to at least pull it up to the level of Dungeon Seige, though maybe keep it Isometric.But a diablo styled Kotor thing would be So So So good.
* - Jsut had a flashback to making doom maps, going to cry in a dark room for a while.