Oh I'm fine with hating her murdering her is just a really really really bad idea.
Unless the Merlin pops up to let us know putting a cap in Mab's head is taking out a critical part of reality's defensive infrastructure, I think executing Mab is just a really really really good idea.
Lest we forget, Mab came within inches of dying in Battleground, but you sure as hell didn't have the Merlin waltzing by to save her ass 'cause it's her ass or the world's. Remember, the only thing that Mab can claim to be doing to protect the world is being the last in a long, long line of guardians.
In Cold Days, Dresden saw the Gates as literal gates in a massive ass wall being defended by Winter against the Outsiders, but we also have word from Mother Summer herself that Mab dying just means Maeve getting control of those forces (only problematic because at that time, Maeve was corrupted by Nemesis and thus the Outsiders).
Literally, Chapter 33 of Cold Days starts with Mother Summer talking about Mab's death and how it's only really bad because Maeve is the one who'll inherit her Mantle. In that same chapter, she shows Harry the Outer Gates for the first time in that context.
Rashid, the Gatekeeper, explicitly tells Harry that Winter is not the only guardian, and will not be the last:
"There are always Outsiders trying to tear their way in. There are always forces in place to stop them. In our age, it is the task of Winter to defend these boundaries, with the help of certain others to support them."
Furthermore, there are even times when the Gates
aren't under siege like what was happening in Cold Days. Again, the moment of vulnerability Maeve would've introduced was dangerous only because the Outsiders were pushing hard at that time (definitely a coordinated plan). While the conflict at the Outer Gates is unending, it is not constant. It ebbs and flows, with quiet times and loud times.
So we kill Maeve. Make sure the next Winter Lady is tolerable. Then make her the next Winter Queen by killing Mab. Problems solved!
(This is a long-term plan, but the problems it solves are mainly the problems the Winter Fae make for humanity; that is to say, all the deaths, suffering, child kidnapping, etc.)