Just here to reiterate how breeding/ev training have no relevance to battling skill. Sure, you can spend hours breeding something competitive, but honestly, what skill does hatching random eggs involve? None at all. The only way you can really compare wifi and shoddy is comparing what the players of each game wants. Shoddy players obviously are just trying to play the game/build teams without wasting their time breeding untested teams. Wifiers, on the other hand, take pride in the pokemon they breed for competitive play. They are not as competitively oriented in D/P; they enjoy working for their pokemon rather than exploring the more advanced mechanics of team building, battling tactics, etc.
This obviously does not apply to the wifiers that use Pokesav. Some do wifi because they enjoy the animation, the excitement, and other aspects that shoddy lacks.
Since battles on shoddy are considerably shorter than wifi battles, players can gain more experience by playing shoddy due to the greater amount of games played as opposed to wifi. This leaves me to think that shoddy players have alot more experience, therefore are better players of the game.