Things in places such as private houses or schools are being rejected. Of course, I agree with this opinion. However, it would be nice to apply the rules loosely in some cases. For example, in the case of murals and decorations that exist on the outer wall of a house or school, the purpose of production is to show them to outsiders. The outer wall surrounding a school or house is accessible to anyone, and it has also become a local attraction by producing various murals and decorations. Of course, it is not possible to have it inside the site, but I don’t think there is a problem even if the outer wall is allowed. It varies from country to country, but in Korea, there are many cases where villagers take the lead in producing murals in each house or decorating the outer wall to make the entire village a tourist destination. In the case of schools, various artistic attempts are made on the outer wall. If we strictly apply this regulation, all murals in a tourist destination called mural villages should not be stopped, and murals decorated or painted by students should be rejected even though they are accessible and can be touched by anyone. I think it is okay to apply the regulations slightly flexibly and allow for those on the outer wall where access is not restricted.
I sympathize with this but this has been done, as far as I am aware, for legal reasons. Niantic ran into problems with a court case and part of the remediation was to ensure that SFPRP did not get used. Niantic are applying the precautionary principle and that is unlikely to change, however much players feel that murals backing onto public space should be OK,
That’s what happened. I understand Niantic’s position.
I agree in principle to your comments but alas is seems legal reasons stop this.
When I first started on Wayfarer I did comment (I did state that I knew this is not criteria) that if you could reach the waypoint without going on private property then it ought to be eligible. Example: A mural on the gable end where the property has no land on that side.
The SFPRP rule is also a bit too basic. I seems to rule as either SFPRP or massive apartment blocks. Example: We have many previous town houses that have been converted in to 4 flats which are eligible. The only difference from SFPRP is that you annoy 4 families instead of 1 
But the rules are the rules and unless Niantic make a statement that those rules have changed it is what we have to adhere to.
Keep looking, you will find eligible nominations, alternatively post your location in Nomination Support and people may scour the maps and give you suggestions.
Good luck.