Barricades mostly. Perhaps pumped-up spitfire turrets attached to the ceiling. Minimal no-deploy around anything. So you can block off areas. And on the other side- cortium bombs pulled from actual cortium, so while you COULD potentially block off a hallway, it would be a bad idea, since the enemy could easily place a bomb that you couldn't get to, behind your own cover. So give each base a completely public cortium silo for the defenders, and the attackers could just deploy an ANT for pulling stuff. This means that base no-deploy zones should not block ANT deployment, just placement of player base assets. Or allow ANTs to put cortium into a deployed sunderer, and pull the deployables from there? Perhaps even make the cortium barricades invulnerable to AV damage besides bombs? Nothing big enough to affect tank fights, just so they don't instantly die to inevitable salvos of rockets or AV grenades that are the obvious response.
