Ok, there is a lot to say here.
1. Tracer has some really, really long legs. I think she might have a higher leg to torso ratio than even Bayonetta. Legs for days.
2. those pants are painted on! I mean literally, I don't think I have ever seen "clothing" that hugs individual butt cheeks so completely like that outside of liquid latex body paint.
3. I'll buy that the pose is sexual, but not only in an extremely mild sense. I find it strange that someone would feel the need to complain about it, especially since it is optional. I like sexy butts, so I personally would like it in, but whatever.
4. the original complaint comes from an attitude I really don't like. The problem, right here:
"This isn't a character who is in part defined by flaunting her sexuality. This pose says to the player base, oh we've got all these cool diverse characters, but at any moment we are willing to reduce them to sex symbols to help boost our investment game."
I have a real problem with the idea that a girl showing off her butt in an minor way (ie, being mildly sexy) like this "reduces" her. I also have a problem with the idea that Tracer, or any female character for that manner, who doesn't have "flaunts her sexuality" on a list of defining character traits can't be mildly sexy sometimes. I think it is good to see mildly sexy women in games, especially when that minor sexiness is a very small aspect of the overall character. Women can be sexy without it ruining them.
And as long as people are playing the parenthood, "I have a daughter" card, I have a daughter. I don't think the Tracer pose is in any way a problem, but saying that a single, mildly sexy pose "reduces her" is a problem. I don't know. Maybe I am just being a bit oversensitive here, but I grew up in an environment where wearing a skirt above your knees made you a slut, wearing knee high boots made you a hooker, and the prevailing opinion was that this made you significantly less than more modest women. I don't like it.
5. I don't think it is a problem Blizzard removed the pose. (that may seem to conflict with 4, but the problem there is the attitude behind the request, an attitude I don't think Blizzard shares.) The dev team could probably care less about the pose and so dropped it because who cares. I don't think they are compromising their art, and Tracer is still plenty sexy without the pose. I mean, she has two other victory poses that show off her butt quite nicely if that is your thing, and I would even argue that one of them is sexier than the one that was cut.
6. While this particular cut wasn't a big issue, Blizzard does have a tendency to make sanitizing changes based on community feedback that I don't really agree with. Female worgen changed to be sexier and less animalistic, the Theralion voice change, removing the part where Garrosh slaps Sylvanas are all examples of Blizzard changing something due to feedback in which I think something good was lost. It happens more than I would like, I think Blizzard would be better off trusting their initial instincts a bit more.
7. The most ridiculous thing about this who debacle is the blow back against it. Are people really choosing "removed 1 out of 3 sexy butt poses" as their hill to die on? Calm down. There is a discussion to be had here, but freaking out like this just makes you look bad. It is really hard for me to come in here and come down on the side of "I would rather have the sexy butt pose" when so many people are making this into a controversy it really isn't.