His comic book persona was really smart and a way badder dude than they are portraying. He was also very sarcastic in the story which is why you’d get the “oh that reminds me” comment, it's just his sarcasm. He killed and raped indiscriminately, had a harem of chicks, including Dwight’s wife Sherry. The comic didn’t portray him as having any internal enemies except for Dwight (because of the wife/iron). His men were basically allowed to loot and plunder as they liked so they loved him.
If I remember the comic correctly, after Negan took Sherry to be one of his wives, Dwight and Sherry still had s e x so Negan branded him with an iron. Dwight was the only person portrayed as hating Negan.
If the TV show is portraying Negan’s men as being happy for him dying that is false. His men would just end up fighting for his throne and things would ultimately be worse off because his men were bad dudes. One thing about Negan, he ruled by fear but he was far from stupid. Lots of psychological warfare, he tried not to bite the hands that fed him. Sort of like the Romans. He didn’t want uprisings and revolts, he just wanted the clans to pay taxes.