I just listened to two previews: KianÃ© and SotA. To be honest... I'm not impressed, at all. I just have been spending the last day working on a cover of KianÃ© with my girlfriend (who's wanted to do some of these for a while, being a linguist, and wanting to tackle some artificial language lyrics). The one thing that really MAKES the original, IMO, is the simplicity.
People who have been around long enough to know my taste in music know that "simplicity" is not commonly one of my most sought-after traits, but at least I know when it is important. Nier's music is lush but very clear and focused: every note counts. These covers just seem to miss the whole point of the originals (as far as I've heard).
I'm all for doing "out-there" covers (hell, I once reworked an early 90s arcade game's music into a 10 minute, Russian romantic piano concerto), but you've gotta build on something that the original is evoking. And I'm just not feeling it here.
But then again, I've only listened to KianÃ© and SotA, so there may be many that are wonderful.