As long as RDF isn't enabled, I don't think releasing the catch-up dungeons really matters that much. I don't believe many people really want to run Naxxramas until they have the gear for Ulduar, etc. when ICC is already out. Unless you're getting carried, it's unrealistic to just get full gear from a raid tier in a week or two. That's kind've where the catch-up heroics help. Without RDF they still have a daily lockout, and you're still limited on the gear rewards since you can't pick what drops and what you win the roll on. With RDF you could just random queue the ICC heroics endlessly all day until you had full gear which would trivialize it, but when it's not there I really don't think it's that big of a deal. Releasing it without relevant gear will make nobody want to run it short of for achievements sake. Also, I think emblems that drop for heroic bosses should update with the raid tier. Farming them really isn't that fast, you're not going to get all the Emblem of Conquest gear possible on the first day or something.
With no catch-up dungeons or updated dungeon badges, you would have no option besides your weekly Naxx raid and crafted items from higher tiers to get gear to improve your character. As long as RDF is not in the game, I think those catch-ups are fine because they don't speed things up by in insane amount, but cut the time you have to farm gear between tiers down to like two weeks (which I don't see a problem with when it's not the end tier raid). Even if you farm Trial of the Champion every day, you can only do it once and the bosses don't drop their entire loot table. With the wide variety of drops they have, and the 1 drop limit per boss, you can't expect to get more than a few pieces from there before you're already moved on to the next tier. It just gives another option, similar to badges, other than strictly relying on the gear from Naxxramas or whatever tier you're geared for. However, I do agree with attunements to an extent. The only problem is Ulduar. I haven't played other private servers, but during my retail experience of WotLK, many players who even killed the Lich King still weren't capable of killing Yogg-Saron. So while the idea is good, because I think you should have to conquer the previous tier to move on, I'd expect an exception of some sort like rather than full clearing Ulduar you just have to kill all of The Keepers or something similar.
Just my opinions on the matter.