If I may suggest, some elemental players have adapted to a strategy where they transform (make) a tree on "Enemy Soil" early and create a one-man army (Scorpions + Healing/Attack spell) that can easily take down all their early defense and easily win...so perhaps you could implement a "Building System" where combining units would take 5-10 seconds to combine (This would include a timer for the elemental user...so he can see how long it takes during the action)
This would give Order and Chaos a much easier time early game...
Also another small suggestion:
-Make the fire/water combine a premade "Bomber" (Then again this could go down the path of "OP"...but it would be easier control)
Edit: I did just find out that they in fact made the health depend on the health of the combining units, so this idea may no longer be needed lol
I would agree with the time needed to combine. The early Treature is such easy harassment and their life steal basically kills any early offense while healing it, and the Scorpions make an approach hard. Longest I lasted against that was maybe 5 minutes, by spamming archers and getting a CA to stop the scorpions and trying to get Speartons. Didn't work, he got like 3 Treatures and a V. Damn. I guess I'm just not good at OvE.
An 800 gold bomber? Not sure I'd call that "Overpowered"
It has a massive stun if I recall correctly. In the video, that one bomber had a large enough blast to stun the entirety of a Spear rusher's attack and take off like a full bar of their health.