Yes constraints are great. My piano teacher would basically just repeat to me like mantra:
- was it legato?
- were you playing free from tension?
- was your tone even?
- were you in time?
Very rarely would he actually ever tell me anything. And whenever I'd ask for more or feedback he'd just loop back to the questions and ask if I was actually listening to myself play. It was a very frustrating start but eventually it all clicked what he was doing was teaching me to understand my own constraints and then also understand what are the outcomes I am aiming to achieve - if I can't hear how even my own touch is how will I ever play evenly.
Was the most valuable coaching I ever got and was probably life changing for me in terms of levelling up my ability to learn new things.
Prior to meeting him I held the belief there was a "perfect way to play" the piano and would occasionally peruse books and videos on the subject. Of course, as my teacher was keen to point out, no body is the same so how can two anatomically different pianists play with the same technique?
If you have small hands so much of the repertoire will be different vs if you have rach hands