I was going to go on about more dropdowns but then the post was too long. I'll go with these two first.
What if Bisharp was RU?
Bisharp isn't really that interesting of a dropdown, despite being a good Pokemon.
The first thing that pops with Bisharp is the fact that it is very similar to Absol in most respects. The only real difference is that Bisharp is a Steel-type and lacks the random Special Attacks Absol gets. Bisharp also has a better physical bulk than Absol, and this, thanks to its typing, allows Bisharp to set up or switch in a easier against foes, because it is immune to Toxic and resists a few random attacks (Most notably Stone Edge), meaning it can switch and threaten the foe with a STAB Sucker Punch. This is actually fairly big, as Absol cannot do either of these things, meaning that Bisharp's Swords Dance set is more threatening to stall, especially when potentially combined with a Substitute.
The extra weaknesses don't matter because Absol won't survive any STAB Fire or Ground move anyway, and even non STAB ones do a lot of damage. Speaking of Absol, it is pretty obvious that it would be hurt in usage, but it wouldn't be unused. Fire Blast allows Absol to threaten Pokemon such as Escavalier, which Bisharp cannot do, although hitting Steelix hard wouldn't be as important because Bisharp's Low Kick against it is basically Superpower without the drop in power. Thunderbolt would also aid Absol quite a bit against foes such as Poliwrath (which may be best check to Bisharp out there) and Alomomola. Absol's higher speed also means basically nothing, as there is no Pokemon that Absol outspeeds and Bisharp does not (there are things that it can speed-tie, but not outpseed).
Basically, Bisharp would be confined to the same role as Absol's Swords Dance set is currently doing - it is a huge threat to offensive teams with a +2 Sucker Punch in the wings, albeit with more switch-ins, making it better. It could also be an All-Out Attacker, but Absol could have a chance to be used over it in that case. Bisharp wouldn't have too much of an impact for those who prepare for Absol, but it would be a welcome upgrade a set that is arguably one of the biggest threats to offense in RU. It wouldn't really shake anything up usage wise other than Absol, however, although it also makes a nice switch into Cinccino because it resists all 3 of its moves, so it might make it drop in usage too because it is pretty much the only common offensive Pokemon I can think of that cannot deal with Bisharp almost at all.
What if Krookodile was RU?
Unlike Bisharp, this thing would be a new kind of threat in RU... errr... a familiar threat that would make a welcome return for older players.
Krookodile has several traits that would make it one of the best Pokemon in RU almost without a doubt. Its Ground/Dark typing is excellent in RU, hitting a ton of different Pokemon in RU for a lot of damage with a combination of Crunch and Earthquake. Its speed is also very good, as it outspeeds Rotom, Moltres, Lilligant, Klinklang, Rotom-C, Magmortar, Kabutops, Gallade, Mesprit, most Uxie, Electivire that don't invest fully in speed, and Medicham, which is a large chunk of the offensive Pokemon in the tier. Also, notice how it can hit all but 5 of the Pokemon I listed for super effecive damage with its STAB moves alone. Its attack is also pretty good and its bulk is alright, although its bad defensive typing leaves it wide open to a lot of Pokemon.
Krookodile could run quite a few sets to success. The first is a Choice Scarf set, most likely consisting of Earthquake / Crunch / Stone Edge / Pursuit. This set is capable of revenge killing a lot of the Pokemon within the tier, and what really makes this set unique is Moxie. There is currently no Pokemon listed as RU that has the ability Moxie, meaning that it could easily double as a late-game sweeper and it would be the best at its job at doing this. A Life Orb set, consisting of the above could also perform similarly, except allowing it to switch around its Attacks. On this set, I see Intimidate being a decent option as well - Intimidate the foe, make them switch out due to their lower attack, use Pursuit on them, and do quite a bit of damage, although Moxie would still be preferred so then it would eventually be extremely difficult to wall. The Life Orb could be replaced by a Lum Berry for burns although Krookodile being immune to Thunder Wave makes this not as important.
Two Pokemon that would get wrecked in usage are Rotom and Drapion - Rotom is pretty much destroyed by every variant of Krookodile, and having it on your team almost becomes a liability with Krookodile because it checkmates it. Drapion, on the other hand, it almost completely outclassed offensively by Krookodile, and its Specially Defensive set is hardly impressive anymore (that and Krookodile OHKOs it easily), meaning that Krookodile would probably make it drop into NU. Other Pokemon such as Uxie and Mesprit would also be hurt by Krookodile's presence, as they get Pursuited, Crunched, and can't do much back to it without prediction, if they even have the moves in their movepool to do it. Poliwrath would rise in usage if Krookodile was RU, because it is one of the few Bulky Waters in the tier than doesn't potentially get defeated by Krookodile (Slowking and Lanturn are weak to a STAB move), and it can phaze it out of its Moxie boosts. Tangrowth is also a good Pokemon to take it on thanks to its high physical bulk and lack of weaknesses to its moves. As Molk mentioned, Gurdurr may find some usage it has never seen before as well because of how well it takes on Krookodile. Overall, Krookodile would easily be a Top 10 Pokemon, if not a Top 5, due to all its excellent traits and the ability to defeat almost everything with enough boosts (try switching Sceptile or Lilligant into a +1 Crunch and see what happens). It would be perfectly manageable as well.