I really like the concept and I believe you put a lot of effort into visuals, but unfortunately that left some other places quite raw. I felt like the introduction into whole game mechanics was lacking. I wasn't sure what this game is about until I played about two rounds. Till now I'm not sure how trenches exactly work and how forests affect fighting.
I found it kind of frustrating that you can't really control the units - sometimes due to fight some unit went stray and didn't want to go back to the battlefield and I didn't have movement points to bring it back. It was useless.
Also, dividing placement of units into phases is tedious. Suppose I want to place a formation but I placed a swordsman in such a way I can't fit a hero into a gap. Now I have to go back, reposition the swordsman, then click "continue" few times and go back to placing hero. It's a no-no.
To be honest I had no idea how was I supposed to hold that respawning horde for two minutes - burning the stakes would suffice only for like one round, and I didn't even know there's healing power up avalible. Since the first battle I was focused on getting to the enemy leader. Cavalry charges were too short, so I decided to attack instead and moved whole army as close to enemy as possible and placed half-circle trench line in front of it. Burned the stakes as soon as enemies came close to it, and after they burned I ordered cavalry charge towards the leader.
It actually worked - the respawn counter stopped and enemy general was lured to my cavalry. When he was done with it I was finishing off the mob, so taking down the lone general with handful of remaining units was child's play. They never even got close to the city, I was having the upper hand the whole time. I got tippy top of commanders, but I'm not sure this is the playthrough you have envisioned when designing the game.
To summarize I think I like the design, but it seems unbalanced. It's really punishing if you buy the dramatic defence narration, but really easy if you decide to dominate the battlefield for yourself. I'm looking forward for seeing more polished version.