SD Nape is good until you run into you run into those Scarf Pokemon that don't mind a Close Combat or a +2 Mach Punch. Unfortunately that defines Rotom-W & Landorus. And on top of that, you have Latios, Latias, Dragons in general really, and even Gengar who can wear you down by LO recoil until he can KO. Oh and of course Rain in OU doesn't help one bit. It's tough for Fire-types not named Volcarona to safely score a boost this Gen. Due to Thunder Wave & Leech Seed even Ferrothorn's not always safe to switch a sweeper in to. If you add everything that stopped him in 4th Gen as well, you to have to remove 2 or 3 Pokemon of most common teams before Infernape can sweep. That's a really tall order for any team and honestly isn't worth it. Somewhere Weavile is whispering to himself "I hate this place. I hate this place. I hate this place. I hate this place."