when someone says the joker and batman are terrible comic book characters but their profile pic is superman....
Joker is terrible in that he's too powerful. He takes out an entire police station with hand to hand combat in one arc, all his plans are perfect and everyone acts just as he predicts. It makes him unfun, if it wasn't for the quips and quirky nature of the character he would be nigh irredeemable. To be fair this trend only really started in the past 2 decades or so but it has knocked Joker down tremendously for me.
Batman just sucks. He isn't a good "character" and what I mean by that is he lacks personality because fans have come to expect him to be a cold, calculating, dark savior and dc has doubled down on that. Batman used to be way more animated and had more faults, now he's taking out the entire Justice League at the same time. Trash.
Superman sucked for literally 4 straight years (new 52) but the base character is still a good one. Still my favorite Superhero though he's not the best (Kamala Khan).