I don't think they are similar players. Wiggins was a tentative, finesse player who was very skilled, but lacked the confidence to put his natural gifts to use. Brown is the opposite of that. He's a confident, physically imposing, agressive player who takes advantage of his athleticism, but lacks skills.
I'm curious about Brown as a possibilty for the Celtics as he's the type of slashing, scoring, athletic SF we could use. Whether or not he develops NBA skills: ball handling, better form on his shot, and a better feel for the game is anyone's guess. He's a high ceiling, low floor kind of guy.