OK, then explain to us how its different then in 5e. How there's some mysterious procedure by which the DM, blind to any possibility that he's got an actual party of characters to cater to, simply divines how hard it would 'really be' to pick a magical lock, or dispel a demon? Or even climb a mountain.And never underestimate the power of willful ignorance by those who favor something and aren't willing to admit or see it's flaws...
EDIT: I'm finding this whole conversation kind of borderline absurd at this point... are people honestly arguing that 4e's default procedure, advice, etc. don't push the DM to assign DC's by character level... is that really the argument? If that's the case what does one use to assign DC's then?
Hint: He doesn't, he looks at the players at his table and he makes up a DC that fits the characters, which is presumably also part of a story with 'appropriate fiction' so that it all seems satisfying to all. That's all there is. There's no other process in existence for this, never has been, never will be. 4e just chose to be completely open and up front about it. Maybe as a result, hypothetically, as [MENTION=42582]pemerton[/MENTION] maintains, there's some difference in bias and DMs produce slightly different results depending on which system they use. I don't discount the possibility, but my guess is its well within the range of individual variation.