Yuki Kajiura definitely stands near peak in my mind. All of her works in a large portion of the Fate franchise and Black Butler has been astounding and entirely completes the atmosphere of every vibe in each scene from the series, which is difficult for me to say for really any other composer so consistently.
Though if I had to pick a contender, it'd probably be Hiroyuki Sawano. He has some pretty legendary work that I never really find myself unimpressed by. Between the Xenoblade ost and Blue Exorcist, Seraph of the End and Kabeneri of the Iron Fortress.. hard to pick.
Contrary to my OP post and this one, Kajiura & Sawano are pretty much hacks nowadays. Always doing the whole "explosion" soundtrack thing that's all bang & not much else.
Sawano's most impressive work in a long time was Sengoku BASARA, but for just about the entire 2010's he's always sounded the same with no variety at all, just blasting horns & electronics everywhere. His current state is so bad that KOHTA YAMAMOTO has to fill in the gaps for him.
Also, his former company, Legendoor, has fallen off big time. Only Asami Tachibana is left there.
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Meanwhilwe, Masahiro Tokuda and Kenta Higashiohji take Sawano's spot for favourite from this century.