If you could get a younger Al Jefferson would you? Having a front court where both players are 20 and 19 would be exceptional. And I would say Kanter has shown the ability to have more range, be a better rebounder and a better passer. Basically, he's a smarter player. And I wouldn't say 6'10 with a 7'1 wingspan is undersized. IMO.
Based on what? He may never be as good as Jefferson, you are basing everything off one game he did good against his young American peers?