I have to agree, Epica sounds very samey, and not in a good way. It also has a great atmosphere (suits the story well) and a lot of good melodies, but it's musically pretty unsophisticated compared to Siége Perilous and a couple parts of the Fourth Legacy. A lot of the songs are redundant - if you've got Center of the Universe, A Feast for the Vain, and Carry On, you've got the whole album. The other songs are solid but tend to, as we said, "run together." Though some parts of them aren't redundant, like the chanting in Edge of Paradise and the opening vocals in Descent of the Archangel. Other than that, though...it could have been ~20 minutes long just as well.
Kamelot power rankings!
Eternity - Solid album that suffers form poor production and a bad singer. Would have been among their best if re-recorded.
Dominion - As with Eternity, but a bit more unique and adventurous. A sign of good things to come...
Siége Perilous - In my opinion, the band's finest album. Still "regal" rather than "edgy," musically more satisfying than what was to come. Poor production, but oh well. Love Siege - disappointed that the band abandoned their instrumentals, as well as their more uniquely structured songs (Providence) and their less conventional ones (Expedition).
Fourth Legacy - A bit of a disappointment - starts the slide into europower, but still better than your typical band of the genre. Glory is nice, and Lunar Sanctum is IMO the band's best song ever, and sounds like it belongs with the first three albums. A lot of the songs are now subpar (Alexandria, Shadow of Uther...meh).
Karma - If I'm trying to abstract away from my own idiosyncracies, this is probably Kamelot's most well-rounded album and their finest "objective" (whatever that means) accomplishment. The title track is incredible.
Epica - As I said above, I find this album extremely inconsistent and redundant. A few standout tracks, but as a whole one of the band's weakest works, and highly overrated.
The Black Halo - Some of the tracks on this album are horrible (when the lights are down, this pain), but some are excellent (Abandoned, The Black Halo, Memento Mori). I like the production on this one - modern and clean, without being extravagant like on their two newest albums.
Ghost Opera - I think most people agree with me here. This is just a weak album. Anthem could have been a brilliant ballad, but it's soaked in cheesy orchestral effects and lame voice tricks. EdenEcho is the only excellent song on it. Everything else is IMO not worth listening to.
Poetry for the Poisoned - Forgettable, half-hearted.