So you are basically asking what if the genders were reversed.. I will give few examples of such situation which will give you an idea of how audience would have reacted if genders were reversed.
1)In hasee toh phasi movie sid was engaged to his long time girlfriend karishma but shared moments with her sister meeta behind her back.. Didnt share any of these things with karishma and left her on the mandap on the day of wedding to unite with her sister.
Public reaction -Aww.. one of the best romcom of recent times.. Nikhil-meeta are such a cute jodi.
2) IPKKND - Arnav inspite of having a long time girlfriend fell in love with his brothers Saali behind lavanyas back.. Lavanya realised it on the day of engagement and broke off the engagement and left.. Arnav and khushi had a happily ever after(here khushi and lavanya were also friends)
Public reaction - Arshi are the best onscreen jodi ever. Drools.
So the conclusion is if genders were reversed majority of the people who are now criticising Mishti would not have had any issue and would have clapped for the guy.
And now coming specifically to my answer.what would have i done? Whether i would have defended Veer or not?Defending ka to pata nahi, but i would have found his role more interesting..and may be i would have defended him also if the role is played by someone who can actually emote and make me connect to the character's emotions like Tejasswi does.