Yeah good point. I suppose they will strongly consider the maps that were endorsed by the competitive Halo leagues. Not a bad thing to keep some of those battlefields for the pros.
I think Pit is adored by the entire halo 3 community, competitive and non-competitve alike.
Bungie will begin to cater to the competitive community more and more however. When they were making Halo 3 (during Halo 2), MLG was just some tiny little group that held little video game tournaments that got no exposure. Now, MLG has a massive fanbase and partnerships with companies like Old Spice, Dr. Pepper, Stride, Doritos, and ESPN as well as Bungie, Bungie realizes how much exposure their game has gotten because of MLG as well as the future potential of the league. Bungie even made every person on the design team for Halo: Reach attend an MLG event in the 2009 season.
Basically, by catering to your average player, you have a bigger target audience. But by catering to the competitve community, you open the door forsponsors and massive profit through the game's exposure by MLG. I bet the MLG community will be happy with Halo: Reach because Bungie knows that this is their only second chance and if they screw up like with Halo 3, the competitve community will most likely drop the franchise/developer (Bungie) for good.