Don't get me wrong I think there are several characters that could use minor numerical adjustments, but of all the characters, Tracer is the only one who is truly oppressive due to her kit mechanics.
I hit level 30 already (Xbox one) and the skill level of my opponents is noticeably increasing. And Tracer spam is getting more and more common.
She is quickly becoming a staple within my group of friends too because she is plain broken.
IMO it is her rewind that is the issue. The fact that she can simply undo any mistake she makes or lucky hit that you get against her as well as use the ability to out play you or even use it to reload her weapon for increased damage burst is just ridiculous.
Her mobility is already unmatched by any other character which means that if it comes down to a foot race to a health pack she wins and she is always going to be the first to an objective and when she does die she will get back to the fight faster than everyone else. Her damage is also very high and her effective range is moderate (better than many) and she is able remove any non-tank within a burst or two from close to moderate range. The fact that she is also ridiculously survivable due to the fact that she can self heal in combination to being able to manually dodge almost anything is crazy.
Rewind should not affect her hp. She should at least have to save some of her mobility cool-downs to potentially escape if she gets in trouble rather than being able to just mitigate damage constantly. Any damage dealt to her needs to stick because she is so good at avoiding damage in the first place and she can so easily get to health packs.
Cloud 9 after their tourny win said the same thing. Tracer is OP and she needs a nerf. Every other champion is pretty close to being balanced but she is just way too oppressive in her ability to harass and survive and pressure without relent.
Oh... and then they give her a game changing AoE 1HK ult that has almost no counter play on top of all that... super...
This character has no weakness and no downside. She needs a nerf. Anyone who comes back and says that her low hp pool is balance enough is a fool. With rewind refilling her hp pool constantly I can promise you that Tracer soaks more damage per life than any other offense character including soldier who has a heal. She soaks more damage than all other characters besides the Tanks and Mei (and maybe Bastion) when all are being played to a high skill level.