I'll shoot straight. All in all, I find the whole empire a lil rough to use.
The attack range is really poor. Earth unit punch speed is slow enough to allow crawlers free cheese. Fire/air attack range is short compared to that of an archidon or wing. The latter units can actually kite backwards out of the fire/air forward attack range.
Fires, a critical part of their play for use of Charrog, the unit vaguely resembling a spear but used much in the same way, are the most expensive unit. This forces the ele player to gather lots of gold to acquire what necessary amounts of fires needed, both for backrow support as a ranged unit and frontal assault becoming a Charrog.
Due to these needs, elementals are very susceptible to early unit pressure (swords/crawlers), and can even get squashed from these in midgame. I force Elemental players into submission with Order from simple sword/archidon builds, requiring nothing but gold. Because the attack speed/range is so slow for elementals, the swords are quick meatshields while I put on the pressure with archidons. I don't even bother to use spears, an elemental air unit would eat one up fast anyway, and they come up slower.
On this subject, their start game is very poor. Many starts will get tossed aside from a word archer combination, and while the castle air is strong, it works just as well as a chaos dead. Targeting 1 unit, you can just continue to abuse swords/archidons to create a force that's easy to sweep with. And let's no talk about the water +fire blast. That's 800g. Let me know when you can save for that, and then time it to hit all these units with a clap.
But the empire does have some weird strengths, yet they are proposing problems. Trees are still an issue. They are just too strong. Just look how many options it covers in deathmatch. It holds position, creates an army in little to no time, and they're free disposable units for any form of suicidal mission for every spawn. Waters are cheap and can easily restore these and Charrogs, whichever you're amounting a force with. My suggestion is switch cost of fires and waters. Fires are more in need anyway.
Last but not least, that Charrog bug is still there. Happens when using burn around the same time as digging.