Double Booster Terrakion and Trick Room Reuniclus are probably the two biggest I can think of. With Rain nerfing Water STABs, Starmie has no business against Terrakion. TR Reuniclus shreds his team for obvious reasons. The team also appears to struggle against stall teams, as the team is pretty weak offensively for what is supposedly an offensive sun team. Keep in mind that no matter what, you're going to miss something, simply because this is not your team and you've never tested anything for them. Just make sure you don't miss any influential threats such as a Terrakion or a Reuniclus.