There was a lot of great music in the 80s but most of the stuff that rose to the top of the charts was pure crap. But if I had to name one artist who was the crappiest of the crap for the decade, it would be Christopher Cross and anything he recorded.
I was not a fan of synth pop at the time (although decades later I came around to it). Depeche Mode, The Cure, not my cup of tea. I have a hard time differentiating between late 80's/early 90's. Fine Young Cannibals, detested their songs.
Nelson had the hair, but they weren't metal at all.
Most of the 80's metal bands get lumped together as hair metal or butt rock or whatever. There were definitely stylistic differences between some of them. Def Leppard goes back a little earlier, to the late 70's, and of course were from the UK whereas LA was the epicenter of 80's metal. Cinderella's second album went in a bit of a bluesy direction. Poison was definitely very schlocky, but I still liked some of their songs.
Some bands clearly were not a part of the same scene/sound. Speed metal and thrash was something different altogether. Judas Priest wasn't really in the same mold as most of the other 80's stuff.
Now Winger you can bash as much as you want. Warrant was pretty cheesy.