It's a good spread. You have the minimum SpD EVs required for Scarfdera Overheat, meaning almost no other special attack is likely to kill you from full health at +0, especially at your HP. Sacrificing a bit more Attack HP is fine it makes you likely to get more Bulk Ups. It only hurts your initial attack power which admittedly isn't as huge an issue. Roo should always have Guts if you ask me. The small boost in punch ower is nothing compared to status immunity, especially since a Burn will outright cripple you. Stone Edge is prefered over Payback since a +1 kills most frail ghosts and psychics on the switch, and Payback is useless against Rankurusu anyway. It doesn't hurt Burungeru as much but he can't touch you anyway so you're free to get enough Bulk Ups and even a burn until you can one shot him, which is common.
Really? I'll take that into consideration
and thanks for the mention of my ev spread.