Kids Reject Old School Piano
Kids reject old school piano. That is a simple truth about today's kids. Old school piano curriculum says: you will read music first and play what you like later. The problem is you will quit before you play any music you like. Every bit of the old school rules are valid, in the abstract, and certainly valid for a concert pianist.
I learned the old school way. The question is, does it work for kids today? Actually, the old school never worked for anyone except those destined for the conservatory. For amateurs, for children, it was the same disaster 200 years ago as it is today. But kids of 200 years ago were not assaulted with TV, phones, computers and a thousand "easy" electronic devices.
Statistics The Old School Has Earned
Elements of the old school are useful, but if you teach only using this method, you're in for a rude awakening: 90% of your students will quit within a year. Restricting a student to only reading music will stifle enthusiasm quicker than anything else. Better to proceed on a two-branched approach: read music separately from playing music.
Reading music can only be done the old way. But playing music can be done in a thousand ways. Blind people can make music, so reading music is only an optional skill.
A Tree With Two Branches
This two-branched approach works well with kids, since it gives them the flavor of playing music while at the same time starting to build the old-school skills. Reading music is not abandoned, but delayed. Playing music by any means fuels their enthusiasm, while the old school work lays the basis for further conventional study. So let's make a new rule for child pianists.
Child Pianists Are Not Concert Pianists
You don't teach hobbyists the same way you teach professionals. This is poisonous for kids. The basis for teaching kids piano should be: interest every child on their own level and at their own pace.
This means letting kids play music by eye, by ear, by number, by letter, by any means that is easy and exciting. After that, see how much music reading they can take. You can force feed a child music theory, or let them explore songs that they like. The choice is up to you.