I am fine with this trend / sub-scene. I like that style of music a lot, and it's nice to be to sort of experience it having missed the boat when the scene was actually like that for real. I appreciate the newer trend of doing this with more recent acts as well (Mamireta, Virge, Mediena, kinda-sorta early Pentagon).
It seems like Starwave is trying to really cash in on this lately, although their groups seem less like nostalgic throwbacks and more like cheap knockoffs. I was going to write a ~official~ ORZ post about what works for nostalgia bands and what doesn't, but I kind of forgot that I started putting something together.
To echo what Dispo said, these throwback bands have a similar feel but never quite hit the same level of "goodness" that the groups they're trying to emulate had (save Metis Gretel, which imo doesn't really seem like they were trying to copy something so much as be inspired by early campy gothic acts). The homage-kei* groups especially, where there could be some added benefit to more "inspiration" rather than "reimagining" (this sounds like Diru vs. this is 4 melodies from Diru deep-cuts strung together).
*I differentiate homage-kei by using it to refer to groups that quite literally copy and paste themes / aesthetics from older, more famous groups. Grieva, Gossip, Dezert, Ru:Natic, + Crucifixion were / are. Cell, Diaura, Vallquar, BugScream, UFJ, + Rounoir were / are not.