Hey Ikarases, thanks for your post. It's on purpose that you can only build a wall on position 1. The wall doesn't give you the advantages that a bunker gives you, but it does provide the same defense as a bunker wall. The only thing you have to keep an eye on is the mortar troopers that are attacking you on the left side of the map. It's up to you as a sniper to provide the personnel you put behind the wall on position 1 enough backup.
Lets just say that there isn't the space to build a bunker on that position so the only thing you can build there is a wall. This does make it a tad more challenging, but I also think it makes it more interesting to have more than one type of bunker to worry about.
"The absence of rules is the enemy of art." ~Orson Wells
tihs disadvantage faces at high probability the mortar hits soldier... thanks for answer 
