I somewhat agree with Boko here. I do think crazy dead man had a good motive, and it was obvious he was after something more then political gain with Yuna.

However, I agree with Kanno for the fact he was put in simply to give you a villian and cause Conflict, as Sin himself wasn't a Villian who could interfere with you regularly.

I mean if you were to take him out of the game entirely, the overall story itself would remain basically unchanged. Sin needs destroyed, and at Yunalesca I don't see any character having any sort of change without dead man being involved.

Don't get me wrong, in a game an Antagonist that isn't really the cause of the main problem can be good, but in the case of Seymore it just doesn't fly. I'd go inot a good Villain like that, but I'd be spoiling a game for someone. Hell, mentioning the game right now would spoil it now.