I have a ton of respect for IGA in the long run. Not everything under his run was perfect, but I think a lot of it wasn't necessarily his fault. He just did what he could given the cards he was dealt. He was putting out games at an extremely fast rate, with probably not a lot of funds to work with, hence a lot of corner cutting and shoddy work. I, personally, blame Konami for stuff like that. If they expect big returns from Castlevania, and for it to be competitive in the market, they need to give proper time and resources to the project. It's smarter business in the long run, I think. What they were doing was shortsighted. However, some of IGA's ideas were bad, like making some of the games bizarrely easy, and switching to that anime style... and Dawn of Sorrow in general.
IGA's managed to make many of my favorite Castlevania games (Harmony of Dissonance, Aria of Sorrow, Symphony of the Night, Order of Ecclesia), some of which rank high among my favorite games, period. If he is getting out of the game business, that's saddening to me, but I will always remember him fondly.