2. Creates New Opportunities For Storylines
One thing bringing in outside talent does is allow for new storylines. Fresh storylines. No more "stable breaks up, one member turns heel, then they're out for revenge" etc. No more "stereotypical heel from unpopular country insults America." How about "MMA fighter invades to prove he can walk over these "fake" wrestlers" or "two fighters come in with unfinished business from another company" or even "MMA champ is such a fan she couldn't stay away" as storylines? That's not to say they'll replace existing storylines either. So maybe "no more" was the wrong phrase. It's "in addition to." They may or may not sound compelling as pitches, but there's no doubt WWE creative could do something with them. Fresh storylines for a company that is running week in, week out is always good for business.