THE PRESSURE TO COME UP WITH GOOD SPOILER TAGS IS GETTING TO ME
Want to watch the world burn, or want to watch M die? I'm fine with a villain that wants to watch the world burn, but that's a separate goal from killing M.
If his only goal (I'm not saying it wasn't (nor am I saying it was)) was just to kill M, and then himself... are you saying that he won? Give or take 5 minutes? What kind of Bond film is this???
I think a villain that kills M in the middle of the piece, and then goes on to do whatever else he has planned is a scarier villain than one that walks up to an old mansion in daylight with 10-15 goons and a helicopter.
LET'S JUST FACE IT, NOBODY DOES SPOILER TAGS BETTER THAN 005