Synchros ruined Yugioh. The 1 tuner 1 non tuner means that players can just splash multiple over powered synchros in their extra deck that has nothing to do with the archetype they are running. If all synchro monsters had to be specific to a card type and/or attribute I could understand.
Synchro is actually one of the worst summoning mechanic due to the restriction lmao (needs both a tuner and non-tuner whose total level match the synchro monster's level).
Compare it with Xyz that can use any monster with the same level, or Link that can use any monster period.
Pendulum's power level would have been as low as Synchro had they not release cards that search other Pendulum....
Synchro deck can easily brick, unlike other summoning mechanic. With Synchro decks, if you happen to draw only Tuners or only non-Tuners, you're basically already dead.
That's why even in OCG/TCG no one play pure Synchro anymore, thanks to Xyz and Link existing. Xyz and Link means if the deck bricks at least it still can summon something else from the extra deck.
Current top tier deck is Darklord, Desperado and Invoked Neos, which are not synchro deck. Six Sams is still good but they might fall down if Konami decide to hit World Legacy Clash