It seems intelligent to conclude that WU will build on the progress that Niantic has made in delivering Ingress and Pokemon Go.   Let’s have a look at what this might include:

Username It’s time to get thinking.  What will your username be?  Every player in Pokemon and Ingress has a unique username.  Where a desired name is already taken, the letters are often substituted with numbers, so HarryPotter might become H4rryP0tt3r.  I would expect Niantic to restrict quite a few key terms such as character and creature names from the start.
Houses Clearly teams will be a key factor.  Obviously Houses lend themselves well to this so surely each player will be able to choose their house when they sign up.

Will they be able to change houses during the game?  This seems unlikely if Ingress is anything to go by.  The process is slow and long winded and designed to dissuade.  Only for the most determined players.

 Locations Based on the use of locations as portals in Ingress, and Gyms/Stops in Pokemon, obviously the WU world will include moving to locations and battling to own them.  Borrowing from Ingress, each location is likely to have levels of defence and protection (using spells?) that the opposition will need to defeat with their own attack options.

In Ingress, all portals are the same.  Every location has the same structure whereas in Pokemon Go there are Gyms (to battle for ownership of) and Stops were just used for collecting between gyms.  In WU I think that different locations will have different purposes as in PoGo.  Some will allow for collecting/earning spells; some will need to be fought for.

Progress Each wizard will be able to progress and ‘level up’ throughout the game.  In Ingress the highest level is 16 with AP being earned for actions such as deploying on a portal, adding mods, linking and fielding.  This is likely to be replicated in WU with actions earning a personal version of House Points.  Attach and defence spells are likely to be earned when each location is visited, or at least a power up feature for a spell already owned.

Higher level wizards will then be able to deploy more advanced attack and defence spells on a location, reducing the chances of other sides being able to capture it.

Battles A key benefit in making WU a game with ongoing appeal is the ability to join forces to battle for ownership of portals.  Wizards of higher levels will be able to attack a location at the same time in order to overcome its defences.
Other player locations Pokemon and Ingress do not let you see where other players are, unless they interact with a location and this is highly likely to continue in WU.  Whilst it is technically possible to ‘see’ other wizards nearby using Augmented Reality, data protection concerns are likely to win over.  It will be a significant risk if a young person (or anyone) can be located using the game when they are not battling to win a location. Not everyone out there is nice and Niantic/WarnerBros Entertainment/Portkey Games will be challenged early on in the press about the risk to children playing their shiny new product.  They need to ensure they can protect young people.

However, it would be very cool if the ability to share locations with other chosen players was introduced, family members and other team players for example.  Don’t think it is likely though.

Spells Clearly locations will need to be attacked and defended.  My speculation is that spells will be earned through actions away from locations.  In Pokemon Go, creatures could be seen out in the wild and this could be used in WU to ‘find’ potions, artefacts,
House Points A winning feature of WU will be a total of House Points for each side.  This will need to be achieved via some team action that can be added to by other players or diminished by the opposition.  In order to win in Ingress, the total of a field’s MU (mind units – that is people that live under it) are added up to give a score for both sides.  But how could this work in WU?
Shields I suggest that each of the 4 houses will build centres of power with shields (instead of fields) over them.  Think Hogwarts being defended when Volermort came to get HP in the last book.  Players would be able to add their own shield to the edge of an existing shield, creating more area protected for their side.  A town might typically have 4 colours with 4 centres of differing sizes that opponents would attack/own/join to their own shields.  Just a thought, but that is how I would design it.