Void Elves are bland because they are just void painted Blood Elves. Blizzard only made them because of Alleria’s story, they were an afterthought.
Tentacles? Voidform? It’s literally the shadow priest theme, so it wasn’t unique. Priests are available to nearly every race, and you feel more connected to the void playing shadow than playing a void elf. The void patch also didn’t feature void elves, so yeah, the void thing isn’t interesting, unique, or doing them any favors.
Void Elf lore is also terribad and non-existent. Many of us wanted Blizzard to do something different with the high elves so they were less “generic” but they didn’t.
High Elves at least never became Blood Elves. They at least had two mounts that weren’t void painted striders. They still to this day have more potential and more room for development than void blood elves.