So I was just discussing this with my friend. Consider the following.
A traded pokemon gives increased EXP.
A pokemon that has max Affection in pokemonamie gives increased EXP.
The EXP Share gives EXP to everyone on the team.
Super Training means you no longer have to care about EVs in wild battles meaning you can slaughter everything.
O Powers at level 3 for EXP gain will increase the EXP you get from battle for a short time.
All added together, you end up with one of the most broken and awesome power leveling system, sure it takes time to set up but could mean training for competitive battles could be easier.
At this point I'm not entirely sure if all the bonuses stack, so I'm going to be doing some testing with my friend soon since this could be great.
A broken leveling system also has to be time-efficient, which this is not.
Exp Share is broken though, I'd say.
I'm unintentionally cruising for a level 100 team prior to post game, not that I'm complaining.