I can tell that this would be that one stage that I would just play repeatedly because it has so much extra content.
The map is cool, as are the extra features. However, the elves are way too weak for such a long respawn. It's even longer than the hero's respawn. Either increase their HP & damage considerably or lower their respawn to something more along the lines of 10 seconds. The hero is cool, though secondary heroes normally have 2 abilities. Especially if their first ability is a passive. (It is, right? That's what it seems like.)
The heal of the priests (Even with the upgrade.) is much too weak to balance out their sub-par damage. I would suggest 50% heal or a damage increase of 15. (For minimum and maximum.) The first ability doesn't have much for me to comment on, so I won't. Regnos' warrior is so much worse than Sagate's in every area. It needs a serious buff.
I don't get the Dark Priest's first ability. Who does he transform, and into what do they turn into? It seems like he transforms Gliders into Bloodsuckers, but I can't be sure because it's unclear. Also, Bloodsuckers should only have average speed, otherwise they're OP. Consume doesn't seem like a good ability. I mean, they kill one of their own for a very minor buff. It isn't worth it.