So, I was originally going to talk about Scolipede (I love that bugger), but then I started thinking about this:
6. Don't just think of these drops one-by-one. All of them would be dropping together, so what impact would they make on each other? Will they help more than harm, or vice versa? Will the Pokemon that rise in usage because of Rhydon be taken advantage of by any of the other new drops, etc? Which Pokemon do you think would do the best overall in this new metagame?
Physically Defensive Amoonguss will DEFINITELY rise. No doubts about that.
Rhydon would be iffy to handle. It cannot 2HKO without a Choice Band, and is 4x Weak to its STAB. While Alomomola cannot do more than 62% with either Waterfall or Scald, Amoonguss ensures the OHKO with Giga Drain after one or two layers of spikes (and hey, guess what, a good, fast spikes user just dropped!) or a little prior damage (remember, Rhydon does not even get lefties recovery!). However Rhydon does hit like a truck, doing aprox 40-49% to both of them assuming Max Atk and Eviolite. Choice Band or Life Orb versions can outspeed and 2HKO both, which is something to watch out for. If that is so, I predict a rise in offensive grass/water types such as Serperior, Samurott, Exeggutor and Ludicolo, the latter two boosted by their respective weathers, so we could see a rise in weather as a result. Whimsicott gets priority weather, so that would certainly help.
What Amoonguss DOES do well, is at the very least check the other three. Whimiscott cannot TOUCH it (uninvested HP Fire/Ice is a 5HKO at best on Physically Defensive sets) while Scolipede can only 3HKO with Megahorn (assuming +0, Jolly and Life Orb) while it can just Clear Smog away any boosts and then switch. Hitmonchan's Adamant Life Orb Iron Fist Ice Punch is also only a 3HKO, and Amoonguss can always just switch out to Alomomola to resist the hit and get its Regenerator.
Overall, a rise in Amoonguss + Alomomola (also, Emboar is gone, so no need to worry about predicting around Wild Charge + Flare Blitz) would be a definite occurance. Weather might see a boost, as would SubBU Braviary and generally any lure (I personally like lure Rampardos myself).
Now, a little about Scolipede, since nobody seems to have mentioned it much:
Scolipede can run a variety of different sets, and its versatility alone would give it a place in NU (kind of like Gardevoir). It can be a Spikes + TSpikes set, one that can actually hit back vs spinners and poison types (though again, Amoonguss is a thing). It can also be a Baton Pass set, as it gets both Swords Dance and Agility, and has a better typing that Ninjask imo. Finally, it can just be a standalone late-game Swords Dance sweeper, with a strong STAB in Megahorn and good coverage options (EQ, Rock Slide, Aqua Tail, Superpower), mostly thanks to BW2. It also has a very nice 112 base Speed, just barely slower than Cinccino (though hey, Swellow is gone!).