Mileena definitely got better but that's because of her buffs (obviously) and better yet, because of the nerfs to other top tiers, some of them were very hard MU's for her, she still has her bad MU's and we don't even know if the changes will stay but the only fact here is that she got better.
I can see her being upper mid and even high tier (I feel like I'm pushing it with high tier but anyway, idk)
People are crying about her B12 staggers, which is good BUT people don't like to lab shit in this game I swear. I think the only characters that have a harder time dealing with it are Kenshi, Takeda and Jason, and by harder I mean that they have to armor more often than other characters.
Mileena has options after B12 but so do all the other characters, people like Kotal, Johny, Cassie, Scorpion, Kitana, D'vorah, Sub-Zero, Shinnok, Mileena herself, Tremor and others have a waaaay easier time against her pressure because of their fast low profiling, long ranged D4.
If Mileena's B12 left you right in front of your oponent and B1 was a true mid I would ask for nerfs myself, but every character has options. Now, I'm now downplaying or anything, her B12 is good but as other Mileena players have said, it's a fair string for sure, once her oponents start using all their options, she has to commit to other stuff. She has good options but so does everyone else. People are acting like this is pre patch Raiden's F12.
About her D1 it is definitely a good buff, even tho it doesn't affect B12 it gives her betted up-close buttons when combined with her D3 (D3 is miles better than D1 anyway). About her new zoning, I agree that she doesn't need it now with faster pokes (it's not even godlike zoning but it is better fo sure)
At the end of the day we know this character is getting nerfed because of dickriding crybabies, so my suggestions are to take away her sai recovery buffs (even tho they have to fix telekick~sai on block) and that's it. B12 has been +2 since May and people never cried about it until now, take several seats guys, like really.