Thanks for playing! Your video gave me tons of valuable feedback. It's definitely super useful.
I agree the line of sight tool is lacking at the moment, it's due for an upgrade.
Micro-terrain has been a known issue for a while, the next map I make is going to be way flatter.
The trees are just cosmetic, what matters is the area of the forest. The reason why they're so sparse is to prevent performance problems because the map is huge.
Some units need to completely stop before attacking (tank destroyers and infantry). Also they're going to aim way slower if they're suppressed (indicated by the white flag next to their label, and under their unit card at the bottom middle). That's part of why that single enemy tank destroyer was wrecking you.