It was an pretty good finale for a show that had become rather dismal.
When the show first started, Richard Wilson commented on the whole Merlin Vs Doctor Who by saying that unlike Doctor Who, Merlin had a lot more room to change and evolve. Even though I was a Doctor Who fan I agreed with him. There was just so much dramatic potential in Merlin and it was a brand new show.
Shame it didn't live up to it. Heck, it didn't even come close. After a while the show was living just on the supposed bromance and whatever excuse they could find to get someones shirt/armour off.
Doctor Who has now been going on for 7 years and out of the two shows it's the one that feels dramatic and takes chances. Even RTD's cartoony Master was more 3-dimensional then the comic strip villian that Morganna had become.