That's not a tier list. A tier list is an ordered list of who you expect to win torunaments while also taking their potential into account. In other words, considering each character is played as perfectly as humanly possible, it's a list of best to worst.
In my opinion Bowser's a bit too high. Sure he fares much better than in melee, but he does not have that much advantages over a lot of the characters under him.
But yeah, expect it to change a few times, also it's not really revelant for our matches here.