Adding characters like Colress and Zinnia seem like filler to me. Actually, thinking way, WAYYY back… that guy chasing suicune was the most pointless waste-of-pixels of all of them. What was his name?
Your question has been answered.
…but fiiiiiine, I can disagree with you a bit if you want. On all three counts, actually. Colress’ detached and rational “scientific” approach to investigating the ideological conflict of Black and White gives a completely different perspective from anything else in that generation, and helps to maintain the idea that, even if Ghetsis and the Team Plasma loyalists are clearly evil by this point, the original point they made is still worth study and contemplation. Zinnia gives us a new perspective on the whole storyline of Ruby and Sapphire, and is just a cool character in her own right. Eusine is a bit of a douchebag, but his relationship with Suicune is really important to the way that Gold and Silver think about their legendary Pokémon; he is the first character in the games ever to have that kind of specific interest in a legendary Pokémon, and thus in a sense the forerunner of everything that happens with Team Aqua/Magma, Team Galactic, and so on and so forth. I mean, I guess that’s “filler” in the sense that it has nothing to do with the notional main plot of winning badges and stuff, but if you think that’s the interesting part of the story then frankly there’s no helping you.