I also run SD Kabutops on my rain teams, albeit with mystic water attached. Same set and everything... a +1 rock slide w/o LO still ohkos gyara.
Arghonaut will cause problems for some important members of your team, any set with recover will be able to switch it and waste your turns of rain. Ohm is a good new counter for him but it could still get dicey. I might recommend swords dance on qwilfish as well, not to turn him into a sweeper but to lure in stuff like argho and vaporeon so you can explode on them (watch out for protect.)
Also, an opposing kingdra that comes in and dragon dances on one of your switches OHKOs everyone. (Not actually sure about that but no one can really switch in.) As always your best bet is to force it to outrage and go to sciz or zong and hopr for the best, but I might recommend changing sciz to CB with quick attack just to deal with foe swift swimmers.
Otherwise looking good, I might start using ohm on my rain teams.
If ignorance is bliss, then knock the smile off my face.