Oh indeed - looks awesome 
As for the limitation - if it is such a big problem that players can wall in enemies, why not let the enemies be able to punch through it slowly? Combined with having to have a digger/crafter go to fill the tile? Seems to be a good compromise between abusing the system and avoiding limiting it for the players overly much.
As for the limitation - if it is such a big problem that players can wall in enemies, why not let the enemies be able to punch through it slowly? Combined with having to have a digger/crafter go to fill the tile? Seems to be a good compromise between abusing the system and avoiding limiting it for the players overly much.