Pretty sure blissey/chansey also walls that latias as it can just constantly break your subs with seismic toss until you need to recover then just toxic you. Also any ferrothorn using gyro ball beats it. I'm sure there are others but that's just based on what commonly beats my sub/cm latias in ubers. There's a lot more counters than just those 3.
But honestly, you might be able to lure kill scizor with that reuniclus but any smart player isn't going to keep TTar in against a reuniclus that's just used trick room anyway. So you're not exactly guaranteed to easily get rid of its counters for the sweep. Then its sweep can also be stopped by scarf revenge killers or excadrill.
IMO, if you're gonna base a team around supporting a sweeper, it might as well be something like excadrill. Just have 5 other pokemon pound gliscor into the ground. Kill off any relevant priority and you're home free.
But honestly, you might be able to lure kill scizor with that reuniclus but any smart player isn't going to keep TTar in against a reuniclus that's just used trick room anyway. So you're not exactly guaranteed to easily get rid of its counters for the sweep. Then its sweep can also be stopped by scarf revenge killers or excadrill.
IMO, if you're gonna base a team around supporting a sweeper, it might as well be something like excadrill. Just have 5 other pokemon pound gliscor into the ground. Kill off any relevant priority and you're home free.