By John Keegan and Gregg WrightAs I've come to expect from "Merlin", the really big plot developments are always saved for the finale, which generally makes them the highlight of any season of the show. Unfortunately, this has the effect of making a lot of the episodes in between feel like filler. This year was a bit better than any previous one in that regard, but it still falls well below my expectations. Still, we're at the finale now, and it's hard not to appreciate it for basically being the kind of episode that we really should be seeing a lot more of on "Merlin".