WWE can't just sign anyone.
WWE can't sign Will Ospreay - though you'd expect, with NXT's move to USA, and the preexisting groundwork laid on Twitter, the company would debut him directly on Monday Night RAW in a programme opposite Seth Rollins. The spectacular worker fits Paul Heyman's profile, and is arguably the best talent on the planet.
He is tied to New Japan Pro Wrestling on a long-term deal.
NJPW has reworked its contract negotiation process in recent years, in light of increased competition, and this also rules out a return for Juice Robinson - not that he seems keen to return stateside. Not all Independent talents wish to sign with a major, much less WWE: David Starr loathes WWE's capitalism culture, where reportedly, Timothy Thatcher in effect told Canyon Ceman to kick rocks.
Despite a recent, and very drastic discourse - two slightly wonky hours of AEW Dynamite have somehow become a crisis in this insta-reaction culture - AEW remains in its honeymoon period. It seems unrealistic to expect a subversion of the narrative du jour - i.e. of countless talent wishing to leave WWE for the mainstream upstart - but then, wrestling is inherently wild.
Contracts in pro wrestling are murky - though Fightful's tall scoops whizz Sean Ross Sapp has compiled a running list of imminent expiration dates - and thus, take the following pitches as estimations...