90s had more style than just Saber's.
And studios don't define the style explicitly, but the art directors associated with the studios define the styles, and when a studio is supervised by the same directors and key animators year after year after year, each studio develops its own style. Studio 4oC has developed its own style seen both under Mike Arias's direction and Masaaki Yuasa's direction because one of the key animators/directors was Shoujirou Nishimi. He's as much a part of the studio as anyone else and he defines their style. Prior to Nishimi holding the position, it was Mutsuo Koseki, who worked for Madhouse and Studio Ghibli before, thus his style for Spriggan was different than what we see in S4C's works these days. Madhouse has had different directors and as such different styles, which is why I specifically stated it'd have to be Madhouse using Kon's or Amano's styles; they'd be able to pull that off, at least Kon's style, because they've worked with it for so long. Now, I would be willing to let S4C handle Castlevania, but they'd have to bring back their old staff and keep Nishimi, Arias, and Yuasa out of it; S4C did better under Kon's and Hidekazu Ohara's direction.
From the sounds of things, what people want is S4C under Yusuke Takeda's direction again (Berserk, Blood, Fatal Fury, GITS:SAC, .hack//Quantum, Sakura Taisen, Slayers: The Motion Picture, Gundam Wing). I wouldn't mind seeing him get hired on for Castlevania.
This post gave me an idea for a new topic...