A good game can ramp up the difficulty the farther you progress and still be playable- provided the player is paying attention and taking the steps to learn it.

I think for Shad, the gloves should come off and slap the people with said gloves who go in poorly geared and actively not being team players. Jump potions will clear you for a major portion of the game. However, by level 70 and the MSQ cleared- players should be able to understand why their gear should not suck. It is not gating off anyone to tell them "Hey, your ilevel needs to be this high for this dungeon/solo instance." It's just a means of informing them that they should know better and the game cannot evolve when some people want to wallow in their own ineptitude.