And yes, to me the best way to learn and become well rounded & great is to work in as many places as possible. A recent example is the development of people like Davey Boy Smith Jr, or even a Lance Archer/Hoyt.
In Japan they still believe in this, as the top prospects always get sent abroad, whether you look at recent examples to USA (Okada to TNA, Watanabe to PWS), Canada (Sanada to Dupree's promotion), Mexico (Naito & others to CMLL, Eita/Tomahawk/U-T as well from DG), or even Europe in a rare case (Liger many years ago, for example).
Look at Dragon Gate. Certainly a unique style, but they still send all of their top prospects abroad. Shingo, YAMATO, Tozawa, the Millennials group I already mentioned, and the thing with DG is they send these guys all over the place, Shingo to ROH, YAMATO everywhere, Tozawa to the Anarchy system & other places, etc.
I think WWE should hire trainers with all sorts of backgrounds and teach these guys a little of everything. And send them on excursions.