In my opinion, the most profitable thing that WDW has that they would love to recreate more of at DL is World Showcase / Illuminations.. er.. Harmo... whatever they're calling it now. It is essentially a beautiful mall that you have to pay to visit, pay to shop at, pay to eat at, and pay to get really good seating for the nightly light extravaganza while you pay for your very expensive drinks.
WITH HARDLY ANY COSTLY-TO-BUILD RIDES.
They have sort of retrofitted DCA into being a place kind of like that (World of Color, Food & Wine Festivals), but it's not optimal. They know DCA has no romance to it. It's easier to add "fun rides" to DCA than to make it an atmospheric place everyone wants to linger. (They've done their darndest, but it will never be NOS & Rivers of America.)
The Toy Story lot is not much space. They know they can't blow the acreage on a Galaxy's Edge that might not hit the spot. They also know it would be more optimal for them to create urban lands rather than simulate wilderness (a berm of buildings can cut much closer to the edges than a berm of trees).
The OTHER most profitable thing that WDW has which they would love to have more of at DL is pricey hotel / DVC rooms. The old Westcot plan was going to have the shops, restaurants & rides on the main floor or deeper, and all the 2nd floors and up would be hotel rooms. Similar to how the Grand Californian stands on top of Downtown Disney, but more immersively - it would be more like a park full of Club 33s.
A handful of single IP lands would probably eliminate the opportunity to get hotel and park double duty out of the Toy Story Lot. I mean some IPs could do it (Wakanda?) but Arendale won't give you very many hotel rooms, and something like a Lion King land cuts it entirely out of the equation.
Ultimately, I think they'll build something that is a lot like Disney Springs, but with more exotic theming, a "few" rides, but mainly atmospheric places to sell drinks and to do nighttime shows, all underneath disguised resort hotel rooms.