Well you guys talk about the films, but, in the books Arwen barely has a role (Glorfindel has her glory moment in Fellowship) and Eowyn does less as well. Granted the books are quite different, but I think most changes served the story/films.
In any case DBZ just has clearly defined major players who changed over the course of quite a long manga/series. You can't get around to much more than main characters, it's just not doable for them I think. Not with the state of DBZ's popularity in Japan (apparently).
Honestly I'm surprised we're getting these at all, I'd never expected that 4 or 5 years ago. I know we all tend to give Krec9 slack for him saying DBZ is dead, but, honestly, it's not that truly alive. It's a resurgence which is great, but it'll never be what it was back in the day. Not even with some new material. I don't think it'll truly die anytime soon, but it'll never be the true main focus of a company anymore I think, not like I don't know, hot toys is such a marvel vvhore. That time has passed.
So, yeah, I respect all the completists and quantity collectors, but... I'm honestly already just thankful I got my faves. Anything more is near a miracle given the circumstances. We ghave a whole lin up of the main characters already, some in different versions even. That is nothing to complain about.
As soon as they release Kid Buu and a bunch of Buu era characters, (and a few more zero's and maybe some other stuff) I will not at all be surprised if the line dies after that. And we'll just see rereleases. New things will come for them to focus on. Keep your expectations low is all I'm saying, makes it all the better if it turns out better.