Another option would be to make tanks immune to AOE damage from Arty and leave it at that. Or at least add an ability that ignores all AOE for 5mins. I think this is the better option because then it would allow tanks time to reach Arty troops and give time to spread tanks but won’t make them too OP.
If tanks are given AOE then m40s and arty will absolutely have no chance to win. A fully buffed maus tank can deal a ton of damage to a single Arty troop and even more with clàss tech for extra damage and defense done. About 5 maus tanks can drop a single m40 in a few secs, if they got AOE e