Flamestrike
Legend
Personally I'd rather fight 6 ogres where we have to be smart about flanking to win, than fight 4 ogres without the flanking rule.
But... you dont have to be smart about flanking.
In 3.x, Flanking resulted in the '5' step shuffle' every single player or monster turn. It was neither strategic or tactical, was mostly all but assured most rounds, and it got boring (and time consuming) fast.
In 5E, with unrestricted movement inside a creatures threat range, its even more trivially easy to get.
The disadvantage of having 2 different creatures attacking you, is, well... you have 2 different creatures attacking you. Its already twice as bad as it would be if it was just the one creature. I see no need to add an extra advantage on top of that.
It overpowers feats like Elven Accuracy and GWM and so forth (easy source of advantage) while also strips value away from Wolf Barbarians and so forth.
Combat positioning is abstract anyway given the cyclical and turn based 'stop start' nature of combat. Im more than happy to leave it out of my games.
It adds nothing of value, and takes far more away.