I guess I would say that it hasn't worked for them for a while. Playlist management in Halo 3 was a mess (part of which I attribute to the DLC fiasco, but that doesn't excuse the rest of it), and it's just continued into Reach. One of the big issues I have is that they keep making the same mistakes over and over with each release instead of learning from it the first time. Snipers has been in every Slayer playlist at the product launch. Halo 2 had it, people complained, it was separated. Halo 3 had it, people complained, it was separated. Halo Reach had it, people complained, it was separated. Halo Anniversary has it, people are complaining, it will likely be removed because it serves no purpose. Can you see how comical that is? People are frustrated because we can see a list of good, solid changes right in front of us that we know are being read but no feedback is being passed down, and this far into their cycle that's not encouraging. Even if we were given throwaway reasons why they couldn't be put into effect, it would be a massive improvement over the 'monthly update listing out extremely minor changes with none of the reasoning behind them' model. Monthly updates just aren't enough anymore. There are fundamental changes that need to be blown through faster than that (Hey, why was Drop Shield in Objective for nine months? Why did Evade replace it instead of Hologram?), or else not enough of the stuff is paid the attention it deserves.
The thing is, they don't learn from their sucesses either. Team Flag in Halo 3 was a blast, people loved it, because Objective was dead and the DoubleEXP encouraged people who wouldn't otherwise go near an objective playlist. What do we get with Reach? A playlist that actively discourages people from playing the game for the objective, where payouts are tiny. It's just frustrating, is all.