have we learned nothing from sombra
While it's certainly true that the practice of a character might not match up to the theory of how he works, Sombra was harder to gauge because her abilities were scary because there wasn't anything like hacking in the game before, so we didn't have as much of a frame of reference. Doomfist is a damage dealing brawler, so I feel we can have a more accurate estimate on his impact of the game.
I mean, I ultimately do agree. We're not gonna know if he's OP until we play him in the game. Whats on paper is not necessarily the same as whats in practice. And even if he is OP, I think that might not be a bad thing for a new character. It's wierd to say, but you want a new character to be a bit game changing before they're brought in line with everyone else.
It's just that he seems so goddamn strong on paper. His attacks are powerful (one of them is seemingly a oneshot), he's got very high mobility (combine his abilities, he seems to be able to traverse the map better than tracer or genji), has significant health with shields protecting him further (up to Tank level HP), his abilities have a very low cooldown, and seems tailor made for to be the ultimate hero for the strongest strategy currently in the game: Dive. He's going to benefit A LOT from the strategies in place now.
So who counters him? Reaper, maybe, since he can probably outDPS him in close range, which Doomfist wants to be in, but they might be evenly matched in this category. Hog, if they bring his hookshot back (but that's only assuming he doesn't miss). Sombra, since he's so dependent on his abilities.
Again, we'll see, because again, he might not be nearly as much of a threat in the proper game as he seems now. But he really does seem pretty powerful.