Let me tell you, as someone who spent a dumb amount of hours during the early XY days. Mega Lucario is utterly unstoppable and unpredictable. Genesect, while very adept is not that hard to predict, check or even counter. Genesect's broken-ness has always been caused by U-turn, as even though you know its merely threatening its coverage moves and it's going to u-turn, you simply can not take that risk, and when you switch, it gets momentum. Even the lure and sweeper sets that lack U-turn, the threat of it is so great it gives Genesect inordinate leverage. Despite all of this no one really struggles to check Gene, its usually choice locked, and if its not it's slow (life orb +1 E-speed is OP too, but still one has access to some quick rock, steel and ghost types), and there are always counters depending on which moves it lacks.
Lucario on the other hand is literally uncounterable between two sets. 112 Speed, stupidly overpowered Close Combats, and lots of priority options made it a complete terror vs. offense. While Swords Dance or Nasty Plot made it a completely unstoppable wallbreaker. Even when literally every team on the ladder had Aegislash, Lucario faired just fine, +2 Flash Cannon, Iron Tail or hell Dark Pulse/Crunch did a ton of damage. Simply targeting Aegislash and taking advantage of its inability to heal were enough, nevermind Bisharp support. Genesect is just not capable of sweeping or wallbreaking to the same capacity as Lucario. Keep in mind Lucario was buffed this generation with the updated mega-speed mechanics.
Kangaskhan, I shouldn't have to elaborate too much. The Seismic Toss set is just mind numbing how dumb it is to play against. Its bulky (dont need to invest offensively!), fast, and needs 1 move to 2HKO pretty much EVERYTHING. Unless you have a Ghost type, its just going to a hilarious amount of damage to a team, much more than any OU pokemon has any right to without any support or prediction. Even if you have a Ghost, its not like Crunch wouldn't sting badly, especially with its 50% chance of lowering defense.
The current suspects in OU, namel Pheromosa, Aegislash, Landorus, Genesect and Hoopa are not on the same level as Kanga, Lucario and Rayqu- I mean Mega Salamence.
They dropped things removed by suspect, the mega stones were quickbanned, also Mega Gengar would 100% still be super broken
Exactly right. I don't think anything that is currently banned should be unbanned. We already know that they are far too overpowered for the OU meta. I love seeing the old suspects brought down however. Even though a couple may end up banned again, it's nice to give them another shot in the meta since they were at one point part of the meta and there was debate over their places in said meta. What's uber is uber for good reason, what's been brought back down has been brought down for good reason. Somethings will be sent up, some will stay. We don't need to waste time by bringing down things like M-Mence, M-Khan, M-Lucario, M-Gengar, etc. when we already know for a fact they won't stay. There's PLENTY to be sifting through, testing, experimenting with, and debating on as is.