You talk like Halo 2 & 3 weren't centered around the Battle Rifle, and like Reach wasn't centered around the BMR. It's all the same.
That's one thing Halo 1 got right, the Pistol was a great standard like the BMR, but the other weapons were formidable if you used them to your tactical advantage. If you got caught slipping by someone with a plasma pistol/rifle, shotgun or AR, you've got the be extremely quick and accurate or else your dead. Halo 2 did this pretty well with the Battle Rifle and Dual Wielding. Where a BR user could come out on top in most situations, but if you let a dual wielder get too close or take you by surprise, you're toast. It made a skilled player play more carefully and tactically, and casuals could come in and grab their favorite combination, spray and pray and get some lucky kills.
I think Bungie lost their way trying to balance everything to be "fair". Every weapon needs its own inherent strengths and advantages. If you pick up a plasma rifle and end up in a long range battle with a guy with a BMR, you should lose. You are at a tactical disadvantage that you shouldn't have put yourself in in the first place. Instead of letting people make their own tactical decisions, Bungie tried to make every weapon viable for every situation. It killed the fun of the game, and made it so that it was pointless to go into battle without a BMR or Battle Rifle.
