They were already boring right after you got them as a pre order bonus in 5. I forgot they made some more after that, but those were a little less boring.
@Brute One of the few costumes I actually bought ever.
I'm playing on the Artemis blood code and by this point you get so much raw power from passives that the usual mobs die before they can even reach you. You also get ice armor which is nice for the Ornstein and Smough fight.
I don't think adding more characters and stages is the way to go if the base game is considered shit. If you add more shit to your shit you end up creating a bigger pile of shit.
I'm doing most of it with NPC characters. Tho I've only played with Louis and Mia. What I will say is that is feels pretty cheesy when you and Mia are both shooting a helpless enemy with a bayonet.