I've been contemplating this system, and I think I like it. A lot.
I think it has many values on many angles, bear with me.
1.) Let's get this out of the way, for Blizzard it is a valuable development time move. If even the most hardcore of raiding organizations cannot clear ICC within a week of its release, that buys them time and lets the developers feel a sense of indirect gratification. It may not be because of their content, but at least months of their work wasn't overturned in a couple days.
2.) It is a value to the 'world first' competition stage. For the initial wings and bosses it won't limit the speed at which people get bosses down, but it will make it so the stage is re-set with every gate opened. In other words if guilds A-E are competing and A blows through the first wing, and E gets stalled on one of the bosses, they have time to catch up and have a fresh run at it when wing #2 opens. Guild A won't like it very much, but guild E sure will appreciate the opportunity.
Then on the same note, severely limiting attempts on the final bosses of wings creates another sort of competition filter. Some guilds can just shotgun a boss down, swarm it 50 times and eventually they get it, where as now, if they don't make the most of their attempts they can be blocked from succeeding first. The guild that makes the most of each attempt with careful inspection and planning will be the guild that takes that title. I may not be one of those guilds going for this sort of prestige, but I can appreciate this more than the guilds that play 24 hour days and just try to zerg every fight for the title.
3.) Philosophically, I think this is really valuable for players enjoying the game. A lot of people get into the instant gratification mode. If they could just win it over night, they would, then they would lament how terrible the game is because they could do that. In gating, again, like #1, it's not the content that sets the ceiling on pacing. This means that even the most hardcore groups cannot win it all straight away, they have to wait. For content design that also leaves room for content to be accessible to lower levels of play. I know some 'hardcore' players would rather a back-breaking challenge, but if it caters to the top 5% like that, the bottom 60% can't get into it at all.
4.) I like that there is not just a front-end limiter in the method, but a back-end encouragement too. It will be as hard as it is to get into, and the challenge can scale up pretty severely it seems for hard-mode accomplishment, but later in the expansion the instance will become more accessible still to the teams that have the most trouble.
From a design concept, one of the guiding lights in WotLK was to make content available to more people who play the game. What fun is an expansion all about the Lich King if you never get to face him? Some may feel that it diminishes their prestige (now achievement dates are more meaningful than the achievement itself, something I'm am grateful for), but I think it's pretty selfish to want exclusive rights to the conclusion of the chapter of a story-based game.
At any rate, I say good on you, Blizzard. I look forward to battling my way in!