Well, I've been testing Nattorei all day. It was good, but not as helpful as I would have liked. I saw that I was really relying on Ludicolo to soften up my opponent's team before going in for a sweep with Kingdra. Losing that fantastic coverage that Ludicolo brought really hurt my team in the long run, even though Entry Hazards like Stealth Rock work so well for this team.
I'm going to stick with Ludicolo for a bit longer, to see if I can get even higher up on the ladder with it. If I notice that Ludicolo is becoming obsolete, I'll swap it out for Nattorei.
Oh, and I'm thinking of changing Meadow Plate to Fist Plate on Breloom. Not OHKOing Doryuuzu with Mach Punch when it's at 100% is insane, even though such a high powered Bullet Seed is great.