She already had her own long standing solo series prior to Flashpoint.

I beg to differ.
1. Prior to this moment Harley has had -numerous- instances of kicking the snot out of Joker and realizing he’s more often than not terrible to her.
2. Harley is no supervillain in her current solo series, she kind of makes it a point that she’s some kind of hero or anti-hero now.
3. It was never a…

Agreed.
They have kissed many many times, and there are a few instances of them getting in on or alluding to it in old DC continuity.

None of their characters have even been remotely true to their long standing iterations, its terrible. Poison Ivy has been watered down and neutered, Joker is transformed into this... shell of anything he ever was, especially to Harley.
“This Joker seems less like the Joker and more like some fetish-ized abusive…