I thought it went like this.
Quests/normal dungeons gets gear for heroic mode of 5 mans.
Heroic mode of 5 mans > Naxx 10 > NAxx 25 > Ulduar 10 > Ulduar 25
Or am I seeing this wrong?
10 man and 25 man are seperate progression paths, however 10 man Naxx helps for Nax 25 intially but is not necessary.
OS10 -> Naxx10 -> EoE10 -> Ulduar10 -> Ulduar10 HM
All im saying from experiance is. When my guild goes to raid ulduar 10. There is me, 2 healer, 1 ret pala that are fully geared in 7.5/Ulduar gear.
We are the most effective in the group.
For example i can put out about 4.2k dps whilst the next dps comes in about 3.8 dps.
After us, everyone who isnt geared in t7.5 has under 3k dps, and to be honest thats pretty crappy.
It's even why we are dedicating evenings to 25 naxx so we can gear up the underdogs.
And i get your point that Naxx 10 is enough for Ulduar, but I can tell that if your only geared in t7 or equal, then its still possible, but your not gonna be going anywhere near as efficient as you could, and maybe its just me, but i have the mindset that unless we can do something efficiently and fast, then we are obviously missing something and need to go back to gear up.
I dunno, it's how i see it.