The only relevant question's been screaming its absence and omission here. So, let me present it: Has Joni always been the more talented player of the two brothers? And what are the main differences between them?
Hard to compare them as prospects since Juuso played 1,5 seasons in Liiga before his draft and still went undrafted. He was always going to be too small for NHL.
Joni is bigger, has better shot, 2 way game and complete level.