Mixed reality friendly spaces are I suspect based on what kinds of mined reality apps you want to make a space optimum for
Magical park and Sharks in the park are smartphone GPS based MR apps meant for running around
-they work well with a open space outdoors
-they would not work well in your house
-they would not work well in any enclosed space (needs GPS)
In a crowded urban park can kids run around anywhere or should parks designate MR running around areas
Microsoft Hololens images have issues in direct sunlight the holograms become translucent In shade the author of this video says they work well.
kids can skateboard on a flat surface, but adding ramps and other features makes skateboarding far more interesting. MR can be done in an barren open space, but I would think by adding physical reality objects to the space it can become more interesting.
Tzuum is a form of Laser tag. You can play it with just your smartphone, but addiong this makes it mioe interesting.
-Some MR apps call for comfortable social seating and a table. ( just providing a table and seats will not work for everyone. I live down the block from a park with a chess table and ergonomically terrible seating. It may be social seating around a table but this park feature is useless for me.
-Some MR apps needs wifi, parks supplying WIFI makes these parks more digital friendly
-MR needs hardware this may be...
- a smartphone
-in some cases a smartphione with special hardware such as a gyroscope
- dedicated MR headset
Not everyone will have these, parks departments can make them available.
This post is not meant to solve all the issues, it's just meant to let park designers know there are issues.
see also this doocument on designing spaces for mixed reality interactions.