(a) I don't see why the forum should be particularly unwelcoming to Premium artists. In my experience, this forum as a whole isn't really unwelcoming to anyone (not even the creators of the countless "looking for artist" theads) and I don't know why you'd suggest that. =/
Unless you equate all the complaints in this thread to us being willing to harass Premium artists out of here if they dare show their privileged faces?? There's a world of difference between being critical and being hateful, just so you know.
(b) Confirmation bias works both ways, you know. If you assume a Premium comic is just pandering trash as soon as you click on it, you'll probably see what you expected.
Likewise, if you assume a Premium comic is the epitome of quality workmanship and artistic achievement simply by virtue of being Premium, you'll probably see what you expected.
I think what people take offense to is the subtle (or explicit) suggestion that EVERYONE has something to learn from these promoted webcomics, as if they are an example of EVERYTHING good that EVERY artist should strive for.
But the truth is that they aren't. Maybe they tend to have popular art styles- 'popular' does not always equal 'best'. Maybe they satisfy the demand of the current webcomic consumer pool- 'marketable' does not always equal 'best'.
Creating a webcomic that's more likely to be picked up and advertised by a company like Tapas is a very specific goal, almost formulaic. It's NOT for everyone.
And I've said this before (many people have, tbh), but just because a comic is promoted at that level does NOT actually make it 'better' than those that aren't. It's simplistic at best to think that you can improve as an artist just by looking at the work of those who've managed to make a little money for a couple of years on a single project.
If you want to encourage people and help them to create better comics, you'd do better to give them advice on how to reach their own individual goals, or at least goals that every comic artist actually needs (better panel organization, better character design, better pacing).
A simple 'Well, that person is popular. Just copy them' is at best insensitive and at worst ignorant and dismissive.