Letting pre-mades meet pugs will end in a lower PvP population as it will DRIVE AWAY pugs. Both regulars and new players.
This is a simple truth.
The EA/Bioware decision to go free to play does cater to a revolving door of players, but they do want those players to stick around long enough to spend some money. Nothing will drive those new players off faster than a bad gaming experience, and letting pre-mades annihilate newcomers will do just that.
It's not a question of skill, experience, or even fairness. In the end, it comes down to money. And you simply can't make money if no one sticks around to play your game.