Symphony & Metallica. Michael Kamen pouring some symphonic goop over various Metallica tracks with pretty much only meh-to-bad results. Sounds very forced. Should have changed the original Metallica arrangements a bit to accomodate for a symphonic reworking. Just pouring a full orchestra on top of a completely unchanged metal song doesn't work at all.
https://www.youtube.com/watch?v=PblCqNxincU
Alt metal band
Dir En Grey and
video composer Akira Yamaoka. One song from their 2014 album
Arche getting a very nice reworking. Yamaoka turns it into a track that sounds like it was always his own and it works damn well.
https://www.youtube.com/watch?v=eOLPdbEIjwo