Houndoom though looks to be a really strong force in RU if it drops. Mega Houndoom will definitely be a dominant threat in RU, with an NP set that would basically eat everything alive with its power and coverage, not to mention its Speed. Very few Pokemon can reliably take on Houndoom except Rhyperior, and everything else either gets set up on or absolutely wrecked. Mega Houndoom has a lovely Speed tier as well, tying with Cinccino, meaning only Dugtrio and Jolteon outspeed it. Houndoom on its own, if Mega Houndoom gets banned, wouldn't be a bad mon at all. It could run an NP set too, and its coverage would still make it nice. It could also run a mixed trapper set with Sucker Punch, Pursuit, and Crunch, and gives us a nice Dark-type especially with Zoroark gone. Houndoom would definitely impact RU.
If Kingdra drops, oh boy it will be good. It is quite a versatile offensive threat, it can run a Swift Swim set, DD, ChestoRest, Specs, or the almighty CritDra. Kingdra will be one heck of a threat, having nice bulk and being able to set up DD effectively, especially with only one weakness, and be able to sweep with Outrage+Waterfall. Specs and Swift Swim sets would be quite scary too (too bad there's no Tornadus to support Kingdra :(), and Hydro Pump and Draco Meteor would be quite the sight. Of course, the almighty CritDra exists, being able to spam Draco Meteors that always crit, it will sting. Kingdra would definitely be a solid mon in RU if it drops, I wouldn't be surprised if it winds up being broken, but since we don't have it as of now we can't really make a judgement lol.