When BC was released in China, it took the top guild seven weeks to level, clear instances (which involved attunements), and kill Illidan.
When Wrath was released, it took less then three days for a guild to level and clear.
What is the common theme? Neither of these guilds had time to farm gear, but that didn't stop them from progressing. No one in the second case could have so much as done any given heroic more then two or three times, much less a single pass through ten man content.
We laugh when someone shows up for a PuG raid in greens, and say that they aren't "ready". But epics don't prevent the situation when your left crying because the 2pT7 mage in a PuG VoA does 800 dps - and by the above examples, best in slot purples aren't "required" in volume to clear content.
What am I getting at?
The people you play with aren't going to jump 2000 DPS, HPS, or TPS - because they get that elusive ilevel 226 they have been drooling over. It won't teach them the best rotation for their class, how to spend talent points / gem / enchant, or cause them to get out of fire quicker.
Most of the people you play with are probably idling at the same level of play that they put forth when they first started drinking from the purple fountain of Naxx, letting gear alone increase their performance (marginally) - unless something is pushing them to improve their actual play.
Push your guild to improve in non gear ways.
The skill level it takes to coast through Naxx right now is low, and unless your keeping your self sharp purposely, you will find yourself in poor shape for the next tier. Imagine that your stuck on a bike with training wheels - you can't take them off, so you need to find crazy things to do to keep improving as a bike rider - like zooming down Spider St. in 20 min, or having all four tires wear out within 15 seconds of each other.
Now I'm not saying that items won't help you. I'm just saying that you should think of items as a coefficient for the player. They bonus they provide is bigger in the hands of an allready excellent player - and gear alone will never compensate for doing your theorycrafting homework.
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