This concern is something we’re paying close attention to in our playtests.
So far, we’ve seen that heroes like Doomfist, Wrecking Ball (and to some degree Tracer), will need to be rebalanced, and maybe even nerfed, to make sure they’re not super overpowered in the new meta.
Changes like the ones we’ve discussed in the PVP Livestream and here in this thread are incredibly complicated. They have far reaching ramifications throughout the game. Your question correctly assumes that they can never be evaluated in a vacuum.