That's fair enough. To me, it was more like Lina and the gang had stumbled into something much bigger than them, and I rather like those types of stories. It also helps that I love Filia, and I don't have the same hate for Valgaav as a good portion of the Slayers community has for him.
Plus, in the final round of episodes they seem to stop being tag-alongs and take back the spotlight, and it even has my favorite Gourry line.
"If you restart the world, does that mean that everything we've been through will have never happened? Well, screw that!"