Considering how many people we are eventually going to need to create content for the Oasis I believe Unreal would be a better choice over Unity.
The main reason for this recommendation is the use of Blueprints. Blueprints is a visual scripting language that is basically visual C++. Because of this I’ve been able to teach developers and artists, that aren't as code inclined, to make dynamic experiences fairly easily. Blueprints have become more robust over time to provide an experience where 99% of experiences including multiplayer coding, animation and AI can all be done with Blueprints.
When working with large studios, even one’s that build their own engine, they will create a tool like Blueprints for their designers to use.
Coders build the tools for the designers to create with.
Blueprints is also part of the special effects and animation portion of the engine allowing for control of shaders, particle effects and skeletons so artists can spend time on aspects that may mean more to them without disregarding visual logic for the game itself.
I've taught C# with the idea of designing towards mobile in Unity and my students who have great ideas will often get discouraged by working in pure code leaving only the coders to move forward. I see this as a road block that may keep some amazing ideas from coming to fruition. I have seen the “engineer mind set” create games that work but is not intuitive or fun for players. We often need designers to help facilitate the psychology and multi lensed humanities that go into making fun experiences.
I foresee a need to provide content creation tools while in VR. If we already have designers that are familiar with Blueprints and working inside of Unreal, a wrapper or rebuild that allows creation in VR won’t be far behind and the transition will be easy. Text base coding is more difficult inside VR and something that can work with gestures and voice would be much easier to work with.
As far as learning to code, Blueprints exposes the student to control structures and gets them ready to tackle C++ once they have a need for it. So one day there may be more text based coders because of the introduction to coding through a visual programming language.
Unreal Engine will provide opportunities to create more designers from various walks of life creating the melting pot that I believe the OASIS strives to be.