I'm sorry if I come across a bit condescending here, but this smells of some sort of ESPN "hot take" bid.. where people say something meant to stir things up. There's a couple of issues tied up in your claim:
First, What kind of "prospect" was MJ in the mid 80's? You can't look at how he ended up and brand him with it in his early years. Jordan was seen as a guy who could jump out of the gym, was explosive, a so-so mid range shooter. He wasn't alone in that diagnosis. Many guys come up and have similar traits, they just don't develop like Mike did.
Second, I think much of your praise for Flagg is warranted. It's exciting to see a rookie come into the NBA and make a splash. The real test is if they can continue to rise, or if they get figured out a bit.
Third, here's a related statement to my initial claim.. it's just too early to compare Flagg to any all-time player. To do so is just jumping the gun, and it's impossible to know. IMO I want to see what Flagg does the next 2 years. Give me 3 years and I'll be able to start to size up if this kid can continue to develop.