Yeah well everyone has tastes. Halo was supposed to be a 3rd person shooter game for the mac. It became a 1st person shooter for the Xbox. It's different. Like Halo Wars and Halo Orion-Titan-whateveristhedamncode. If you stick with FPS, people won't buy it. Just like the Marios.
EnsembleStudios is a good company with a lot of great games so I'm sure it would have been good enough. Maybe they can't exploit the story of Master Chief in a MMO, but they can do it with others, later on in the storyline.
And all you guys see his concept arts so I don't think anyone can judge a game by sample pictures drawed. Maybe even the screenshots "In-Game" are not so in-game. They might use another game's engine, like WoW just to show it is possible to make.
Anyway, now I pray for them to release what they have like it happened with Wolfenstein ET