It depends on what Pendulum we get.
Synchro and Xyz didn't get strong right off the bat either.
Heck, it can be argued that Xyz still isn't that strong right now. It's still not on par to the level of SixSam Synchro and Shiranui Synchro back then.
Six Sam is a dead deck now, it can't do anything vs monster effect. Back then it was tier 0 because the meta was based on spell/traps, so once you get Shi En out you basically win. There was no way to stop it unless using anti-deck cypher soldier/lava golem/amazoness