I can agree that, yes, it is hard to take over an established strip. It's hard to create one as well. I'm using my Deviant Art page (
http://thewindowkeeper.deviantart.com/) as proof of this, not as a submission to take over GodMode. My web comic, "Muzzle" is off to a rough start, but I took what people said, and I'm working with it. Its not the funniest strip (some of them I'll admit, suck, but I'm my own harshest critic) but its one that's personal to me, and I'm willing to change it to make it better. And that's what I feel that, not just Adis, but Saiful Remy Mokhtar, Bobby Crosby, and the team who does Menage A 3, have to keep in mind (again, me not having a way to check how many page views any of these comics get does put me at the handicap of not having all of the information to make a judgement of "failure" or "success"): Change the strip, adapt to what the strip started off as, or quit (or take a break, but let fans know about it). And in my opinion, I don't see how Adis' version of GodMode is wholesome, my main example being the "Left 4 Dead" strip, but it may also be because I'm sick of "Poo" jokes. I see enough of those on TV as it is.
What got me into GodMode was the innovation of the storylines (personally, I loved the "Man Test" one), and with Adis taking over, I feel that the innovation is lost, not to mention the sporadic, at best, update schedule is, as well, a turn off. And yes, a change in artist will usually cause a rift with fans. As a mainstream example, Brian Haberline took over "Spawn," and made it more realistic and gritty. Personally, I loved the change, but when he quit due to his wife giving birth, and he wanted more family time (something I can fully respect and understand), Todd McFarland took over his own creation, only knowing certain things about the continuity (while a lot, it still wasn't everything), and ruined it by killing the main character. While GodMode hasn't done anything that drastic, its the best example I can think off, because while now I'm against "Spawn," (and most mainstream comics, as well), there are still a lot of fans who have and haven't voiced there opinions who do enjoy the strip. And, just like those who like the change of pace here, I'm not going to say they're wrong, because everyone has there own opinions.
Again, the link above is not for consideration, but as an example of how a comic, web or not, may need to change (if absolutely needed). Even if I was considered to do GodMode, I'd have to turn it down due to my school, work, and trying to start both a humorous web comic, and a horror web comic. My updates for a third would be horrible, and I doubt with that, and the fact that I'm still trying to find my humor voice (my horror comic, "Goria," has an almost perfect tone in writing for what it is). Personally, I feel I may do the comic even
less justice than Adis, or any other artist, has or will do.