I think Rotom Wash is super underrated right now, I've been running timid offensive volt, hydro, wisp and nasty plot with leftovers, and it's been great vs gambit, hsamurott, tusk, skarm, dirge, landorus, pex, and can set up on and take advantage of mons like gliscor, ting-lu, heatran, clef, and ghold that may not be prepared for nasty plot (especially gliscor gives a huge amount of opportunities), and can even serve as an emergency measure vs something like dragonite or weavile. A lot of this may just be since people don't play around nasty plot, but even then, I feel that B+ or A- is super reasonable given the work it puts in even just as an offensive pivot if there aren't any opportunities to nasty plot (though there usually is) due to the good matchups against much of the top viability mons.