Played this today and I really felt the need for a hud showing the dragons' health! Sometimes it felt like I didn't damaged it at all even if I did.
Also would be nice if grenades would explode on impact with the head, would feel better than throwing stickies and explode them at the right moment.
And then what does usually happen with mechanics when it runs out of health? It explodes ofcourse! It doesn't turn to the other side

Having setup time on a map which both teams attacks and defend isn't something I'm a fan of, I think it would be better to just remove it. And switching sides doesn't really fit into this kind of map either.
Last, the dragon's a little buggy when going near it, pushing ppl into the ground, ppl getting stuck beneath it kinda flying with it etc. I think putting a "clip" block around it would prevent people from getting stuck so easy.
Then a question:
Does the dragon regain health over time or can you perhaps "heal" it as an engineer? Could be an idea if not..
(This experience is from playing ds_extractum only, the server I played on didn't like mystic ruins, much because of the dragon's lack of health)