I think its best Described as this.
IGa's Story telling is Pretty bad at times, but Pretty good overall, Sometimes I think he puts the game before the story which is good, but forgets to put story back into the game at times.
Looking at from game to game, I really gave IGA more Crap than he deserves, but most of the crap comes from the Demon Castle War that Kept being mentioned in Irrelevent games.
Ironically SoTN was his worst since there wasn't much story, and it was very all over the place, The Richter Being Evil made sense, but the Maria scenes could have been better, Shaft's Return Was both Senseless and Unexplained, and the whole Dracula seeming to turn good at the last moment made made little sense too. Bute it made up with Half of an Awesome Game, the Inverted Castle... well, Felt Rushed since you can just rush to the OP items and the rest of the game is a cake-walk, The Story's main flaw is that it really didn't have much to go on... But there were quite a few potential cutscenes that should have been there to develop Alucard more.
LOI was another Example of Bad Storytelling, but unlike SoTN, he had ALOT to work with, but ended up with short talk with Gandolfi about subplots that went nowhere. Honestly, I would love to Remake this game With a Better Story, Not Changing it. What should have been done is Major development on Walter and Scenes with Mathias throughout the game slowly getting itno his psyche on his decision of turning into Dracula, Joachim had enough mystery to him to develop a whole story, and there could have been flashback scenes with Gandolfi's Daughter. The game was pretty good, but I felt that the Story overall was Lazy given the fact of have so much to work with.
PoR was So-So, I don't have much to say about it, it has good points and bad, but overall averages itself out.
DoS was pretty good, It wasn't too bad, but it lacks anything interesting since AoS did the Same plot before, Dario could have had more development and the Dimitri plot made the story more enjoyable, the development of all the god guys is a Strong point, but the lack of development of the bad guys brought it down a bit.
OoE Had one of the Best Stories Since It Developed all of the central characters enough to make it good and give a plot twist that is also suitable, the ending is actually very good and bursts with a bit of emotion, I want the next game to follow this in terms of story telling by developing characters, although I welcome more unique ways too.
AoS Also is one of the Best Stories, You Play as Dracula's Reincarnation amonst a sealed castle, the Side characters are developed well and you get why Graham wants to take dracula's throne, only Con is that Soma suffered from typical Anime Protagonistism Early in the game (always confused, doesn't understand even the basics), when the true Soma started to shine the game was awesome.
HoD is one of those overlooked games, it Doesn't look appealing nor sound too appealing, but that's mainly because the GBA couldn't handle this game, Wow, this is the best IGA story, It felt like the game SoTN should have been, although quite a few elements were from SoTN, The Sequel to Simon's Quest Made sense, Maxim's Portrayal was top knotch, although the final Dracula fight was Grotesque, the game overall was gold tarnished by the limits of technology, this I would love to remake Simply by giving it better Graphics and sound.
last but not least, CoD, Great Story all the way, but a Castlevania Beat em up isn't the best game, Fun, but doesn't fit the glove.