IMO this is the core problem with shonen, and it stems in no small part from the genre being more-or-less all about power fantasies for tweenaged boys. When an author starts with that power escalation, they've doomed themselves to writing shit, because if you get into a Lensman arms race with individuals, sooner or later you'll arrive at the point where everything about the premise is batshit insane in the worst possible way. Especially when it devolves to characters asspulling random I WIN moves, or worse, antagonists who aren't actually a challenge and just have a stupid gimmick or keep running away.
This is exactly why the best series are always those where the characters don't so much get more
powerful, but rather just get more
clever, and lot of the fun of the series comes from introducing a bad guy with some crazy power you would never figure out, and watching the main character trying to figure out what exactly their power is while trying to figure how to use their small power to counter it. Take a look at a lot of the sub-plots in Toaru Majutsu no Index and it's side story stuff. (Not so much in the direct main story, once you involve Touma a lot of the story lines boil down to "run in, get beat up, and punch-out the invincible bad guy". The side stories and background characters tend to prove much more versatile). Nobody ever really "levels up" in those series, they just learn how to use their powers to counter whatever is happening with the new bad guy's powers.
On a Wheel of time anime I think it could turn out to be either really good or really bad, depending on a how exactly is was changed to script form. On the note of length I'd like to point out that even if you cut the length of each book in half due to just empty descriptions and whatnot, the length of each one still comes out to around 400-600 pages. I think that while it might not be quite the 100+ episode length, it would still have quite a substantial length.
On the note of balefire I think they handled it pretty well. It's a very powerful weapon, but other then Rand (who seems to whip it out at the drop of a hat) most of the characters seem to treat it like the weapon that it is.
Though I'm pretty sure Rand had figured out that balefire was the only way to permanently kill the Forsaken by the end of it, which might explain why he was so willing to use it (and the fact that he was very insane for quite a while; not caring about the fabric of the universe other then that it still exists makes you more likely to use things that hurt it).
It doesn't just become some magic "super-special attack that automatically wins" type thing at all, but retains its seriousness right up through the last book.