I would hardly call a few j-pop songs worth lamenting over.
They are worth lamenting over. Ring a Bell in particular is one of the most painful losses. The other thing to note is that most all of the vocal themes taken out are more interesting than what gets left behind. The Valkyria theme is a short loop, the EXA overworld theme sucks because it's too mellow, Fury Sparks is boring (=P), and the two other God Eater Burst songs aren't as catchy as Over the Clouds.
I mean, I'm not "j-pop or no buy" but it's a clear loss.