Saying the only thing we have seen from Kushina is survival of the kyuubi extraction is fallacious. Although it is true we have only seen her chakra chains, they are enough. Gamabunta placed on 100% kyuubi could barely keep him bounded, while Kushina while she was nearly dead was able to make him move as if he were a doll with barely any chains. Now imagine her at full health using many chains, doubt anyone can fight her while this restricted unless they use genjutsu.
Claiming What-if's to create favorable scenarios on your side can be done as well on the other side regardless of the topic or situation. (e.g. What if Naruto did not have the kyuubi, but had both his parents to not only make him much more intelligent then nearly every other shinobi, but also teach him most of what they know. Naruto with rasengan, FTG, FRS, Seals, summonings, Sage mode, high levels of chakra, and high levels of intelligence over Sasuke or Obito).
Saying Madara fights with his own powers shows how well your reading skills are. Madara received the rinnegan from Hashirama's senju DNA, meaning Hashirama's power. Madara received his EMS from his brother, Izuna Uchiha, not his own power. I would love to see Madara 'pawning' Naruto without Kabuto/Orochimaru's power, not his own, which is eco-tensei, do you really think he could still be fighting after this long? I would love to see Madara or any other Uchiha attempt to hold a bijuu without dying, while Uzumaki's are hypothetically made for that cause.
Uchiha have no rivals? They don't seem to be as strong as they were stated in the beginning. Most of them are fodders except for the few we know (Izuna, Madara, Obito, Itachi, Sasuke, Shisui) the rest are mere fodders or Asuma level at most. What can good eyes do when the user cannot react fast enough to them? If you recalled the lee vs sasuke fight, even when he had the sharingan, if an uchiha's body isn't fast enough, he wont be able to use his eyes tot heir full potential. Itachi took out his entire clan as a teenager, this just shows how easily it could be done by a single person who barely has chakra. Shisui got destroyed by Danzo, and got scared to the point where he ran away, while Sasuke destroyed him without ems. This is just showing you that your beloved clan isn't as strong as you make it seem. Current Uchiha clan (using their own powers) would be Sasuke and Obito. Sasuke with his own power (no itachi eyes) would be blind. Obito with his own power would have two ms and half a face/body. These two would lose to the aburame clan, inidcating what a joke the Uchia's are without others powers. If they don't use their own powers, Sasuke would have EMS (He can see!) and Obito would have a MS+Rinnegan combo. This being said, they still would debatably lose to a Bee+A Combo.