Yeah, I don't necessarily say that redos are "always bad," but I always warn that they're a trap and advise against them.
It can be very tempting to look backwards, and the problem with webcomics is, your older pages are ALWAYS going to be exponentially worse than your current pages, because you're constantly learning and gaining in skill. Once you've redone some of those pages that bother you, it's going to be harder and harder as you go to not look back and see the things you could do better now.
I'd also be very suspicious of redraw impulses for art that's so recent. "I just finished these ten pages but I figured out a way to make them better, should I redo them?" No, friend, I don't think you should. That's just fussing. Your pages will often be imperfect, and being able to let them go is an EXTREMELY important skill, in webcomics, especially.
I agree with this. As a reader, I don't reeeaaalllyyy care about redone pages because, like, I already read that part of the story! And if that part of the story changes at all, it's frustrating to have the creator go "no wait, that didn't happen QUITE that way, hang on, lemme fix it" in the middle of the story. .........And it's worth noting that many of the times I've been following a comic that decided it needed to go back and redo its beginnings, I liked the redone version less.
It's like, when George Lucas created Star Wars, there were a lot of shots he wanted to shoot again and fix, but couldn't, because they couldn't afford to do the special effect more than once. When he released the new version of the Original Trilogy, he couldn't understand why fans hated it so much -- he was finally able to fix all those mistakes he'd hated for years! But so many people feel he made them worse.
If you look at everything, and you understand that it can be frustrating for readers, and that looking backwards is a tempting trap, and you're able to do it without current updates grinding to a hault, and you've considered the terrifying prospect of accidentally becoming George Lucas, and you still think redoing these pages is going to be a better use of your time than focusing on putting those improvements to use in pages to come, then............ yeah, you can redo old pages!!
But it's good to be very wary of doing it, because very often when we want to redo pages, the only thing it's doing is assuaging our insecurities as a creator, and not actually helping our work or our comics or our readers.
One last thing: The point when redrawing is ALWAYS okay is when your pages aren't finished yet. If you find this desire to rework stuff for pacing reasons is happening a lot, it may be a sign that spending more time on thumbnails and sketches, or working on thumbnails in batches so you can get a good idea of pacing, would be a help for the future!