10 Most Random WWE Appearances
4. Jushin Liger Works NXT TakeOver
WWE has very rarely opened the Forbidden Door because it collides with the manner in which the promotion markets itself.
WWE is the "recognised leader in global sports entertainment", and as such it suits them to treat incoming talent as a level below "their" stars (even if "their" stars actually became stars outside of its flawed system, which is even canonical in the case of Drew McIntyre and Cody Rhodes). With very few, rule-proving exceptions, like AJ Styles and Shinsuke Nakamura, WWE won't allow a debuting act from even a prominent wrestling company to compete with its top stars.
What would that say about WWE? It's where the best of the best are meant to be.
Jushin Liger was different, because he was Jushin Liger: living wrestling royalty as great as he was influential. Wrestling would be an entirely different and significantly worse industry without his contributions to it, and Triple H, recognising this - or attempting to babyface himself ahead of seizing the throne, which is actually fair - made the unusual move of bringing Liger in to work Tyler Breeze at TakeOver: Brooklyn in 2015. The match was more fascinating and refreshing than particularly good, in truth, and the further dates mooted never materialised. Liger was under NJPW contract at the time.
This was a bold move, but one that WWE rather quickly walked back - which may have compelled Bryan Danielson to realise that he was better off jumping to AEW six years later if he wanted to work inter-promotional dream bouts.