No I don't think they are crippling for anything.
They are meant for a style of play where things in-world that are interacted with are by default meant to scale to the level of the party. What I have seen done when I, or others who are not fans of 4e, state this is... various 4e fans do mental gymnastics to claim this intepretation is wrong and that the DC should scale with the party level only if the fiction matches a challenge for the party's level... otherwise it shouldn't. GreyIce on the other hand used an example of a burning building as the fiction and stated the DC's would scale with the party to create narratrive difficulty. Basically saying that regardless of the fiction... it should be dramatic and thus everything should scale to the level of the PC's. His way ultimately boils down to a system that assumes scaling per level for damage and DC's... which is the opposite of what I have seen you and many other fans of 4e argue when stated by a non-fan as a reason they don't care for the system.
Uh, no. This is this and that is that.
The example given in that thread was "You go to the city of brass at level 21 and all the doors have one DC. You go back at level 26 and all the door locks have a different DC."
I mean there's compounding absurdities there (all the door locks have the same DC in the city of brass, no matter what? Disregarding when you went there, WHAT?), but in general it's a setting. It's sitting still.
This is "Back in level 3 we were fighting in a burning barn and it did this, now we're racing through the nobleman's mansion, trying to save the visiting princess and as much of the nobility as we can, while Drow Assassins are attacking us. And the fire does something different! How can you be so inconsistent?"
The answer is hah to you, I'm making a different scene. Yes, if you somehow revisited the barn you burnt down at third level, and rebuilt it, and set it on fire again, I probably should use the same damage expressions. But in the burning mansion I don't feel a need to because it's a different setting, a different story, and you want fire to be exactly identical in all circumstances. Do you see how anal and ridiculous this is? Do you see what sort of shackles it throws on the DM?