These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
Ensemble Darkhorse: Machus the Sword, Urthblood's fox captain, is among the series most popular characters.
Jans and Broggen, the mouse/stoat duo, has also gotten a lot of attention.
It Gets Better: The Crimson Badger was mostly written when Highwing didn't think anyone else would ever read it, and done for his own pleasure. One thing that survives from this period is that the first couple of chapters, after Urthblood reveals his prophecy about the coming darkness, mostly consists of various supporting characters going about their daily chores which, while introducing and establishing characters that will become important later, doesn't really add that much to the plot. It isn't until chapter 9, when the badgerlord's army arrives at Redwall, that things start to get really interesting, and even then it isn't until Interlude with Hares that we truly get to the central conflict of the story.
Seinfeld Is Unfunny: By the time the novel was written, the whole concept of "noble vermin" was still fresh and unusual, and it is one of first Redwall fics to discuss and cover it to such an extent. Nowadays however, it's rare to find a Redwall fic that doesn't include it, or that plays the Always Chaotic Evil mantra from the official novels straight, so this aspect might seem rather conventional to new readers.