well not not sure about after the patch but before the patch to counter this problem I rush out with a single calvary unit and attack their ladders and rams unit just enough so they drop them then i get the calvary back inside the walls, but instead of going to pick the equipment up they join the line the for the siege tower where i haven't noticed any major performance issues of unit gathering unlike the ladders issue. Then its just easy pickings or once their numbers are down you can sally out and get them in the back while they are in line.