Im kinda split on it. I dislike nerfs, but for the sake of game balance I can get over it. Tieria was everywhere (Elson too in the arena), It's a shaky line between "really useful" and "gotta be using it". I like how they are handling it though, returning all resources used to upgrade and strengthen the unit so the only thing you're losing out on is the bookmarks to summon it (in Tieria's case). Maybe they will return those too?
On another note, has anyone 6 starred a support unit? Im getting ready to be able to pop another unit up and cant decide which. My main "tank" and Lorina are 6* already, Destina is the only other unit I consistently use in my groups, do supports really benefit from those extra 10 levels as much as dps do?