Previous TFT had a ton of 2 Set bonuses. One of the most powerful ones was Dragon which was way stronger than Crystal or Steel at raw survivability and all the Dragon units are high impact.
I feel the balance of Set 2 is poor but its definitely not something like the numbers required in order to get set bonuses. Even the ones that could be really abusive like Cloud or Desert are not that impactful given their numbers are pretty low, they're good add-on synergies but they don't break the game.
Honestly I feel the most broken ones are 3 breakpoint synergies. Poison, Inferno, Light, Summoner all come to mind. People are really insistant that Mages and Olaf comps are busted too, which both need 3 breakpoint synergies and the 2 breakpoint ones that fit in are secondary to the main power of the comp.