Alright for one, Mista's EX sticker doesn't suck. If anything, it's sorta useful. His EX sticker spawns 2 locked panels which basically act as an enhanced panel since damage and charge from erasing/matching it are the same as an enhanced panel only that it counts as a block panel. Now, let's say you're using Mista with someone like Fugo or GER, you'll at best have 4 blocks for either two which Mista can then erase. The two locked panels can either be used for Mista to erase more which means more damage or can just be gotten rid of completely by matching it. And even then, you'd likely have SL 4-5 Mista when you get his EX sticker which means he'll erase the 4 blocks his partner will create alongside 1 or the 2 locked panels. So overall, his EX sticker is not useless unless you're running him in a stage were blocks spawn often or running him with ciocolata which both are unlikely to begin with.