Genji isn’t broken.
He is strong.
A good genji is good to have on your team, but not an automatic game winner. It seems from OP’s post, he is more concerned with smurfs than with Genji.
I am NOT a Genji player, my speciality is hitscan, put me on any kind of projectile based hero and I will underperform. If I was to play Genji in my current rank, I would be flamed out of the lobby. Same for Doom, Mei, Hanzo, etc etc.
As much as I loathe to admit it, Genji takes a particular skillset that I simply don’t have, despite him being in the same category as tracer, my main hero. I’d like to learn Genji but I don’t want to drop the probably 700SR required and throw those games playing him.
Genji, like many other heroes, has his strengths and weaknesses. Put him against low mobility, squishy targets, like widow and he will shine. Put him against anti dive heroes like Torb, Brig, Mei, etc - he will struggle.
The problem lies again in bad coordination. A Genji who can punish mistakes without feeding is going to cause problems for your team unless you coordinate against him. The same goes for Echo, Tracer, Doom, and any other high mobility hero, (including tanks, like Ball).
As a final note, in ALL tiers, Genji is middle of the pack for winrate and only has a high pickrate in Platinum and Diamond.