So Wood Elves play completely differently from most other factions. I know TWW3 changes things up, but I don't think this changes.

For one thing, your main objective is healing the forests, not necessarily having full out wars.

If you aren't playing as Sisters of Twilight, I do think those campaigns are a bit harder, but only a bit. Peace out with the Fey Enchantress. Stay in your woods. Don't go anywhere near Grom. Look for easier prey, like Karak Norn.

Don't be afraid to turtle awhile until you can afford to keep someone back to guard the house. Also, build all defense buildings asap.

Abuse Ambush Stance. Invest in those Blue Line ambush techs. (I also invest in Wonders of the Forest for more cash.) Other campaigns, maybe you stay away from something like that, but Wood Elves need it.

In battle (sounds like you are having the most trouble here) you don't need a line. Don't even make one. Cavalry? I guess you have Orion, so you'll start with some. Keep those boys in the trees until someone starts to route, and then chase them down. That's all they're good for.

Your main deal is to concentrate fire on someone, get them routed, chase, keep you units moving, and NOT TOGETHER. Your missile units are faster than the infantry you fight. It is micro intensive, especially at the start, but if you dig it, it's fun. Use the 'slow' setting on the camera and get used to the rhythm and flow of the hit and run dance you want to orchestrate.

I think the Sisters of Twilight make everything much easier, because they start on a hawk, and they are deadly against early game infantry. Once you get the dragon it's a lot easier as well. But it's a DLC so maybe you don't have that.

I'm on like turn 80 of a Sisters of Twilight campaign right now.

I might try Orion here in a minute and see if there's something new in the way that makes it harder than it used to be.