Whats the difference if i may ask? Not talking about technical stuff, sure, the coding is left for the Blizz guys but the design? I guess those nolifers know a lot about encounter design and other players know a lot about quest design, class design, what is fun and what isn't, what works and what doesn't and so on.
I really doubt that a Blizz designer knows more about encounters than the hardcore raiders for example. I mean, it's not like those people are just playing the game, they analyze the shit out of everything.
And i bet that even casual players can tell the blizz guys a lot about what works and what doesn't in their creations. I mean, look at all the failed features Blizz added over time and the countless ways of improving them suggested by the community.
Sorry if i'm not in awe about the Blizz Designers.
But it would be the same difficulty for both, thats what important. Today you have the same situation, just with the difference that world-first Timmy, aside from his skill advantage, has a ton of much better gear, making Torghast much easier for him than for low-skill Johnny.
It's kinds stupid that the low skilled players get a much harder difficulty than the high skilled ones.