You make a good point. It’s a long season, and a longer rotation could save wear and tear. But there is a natural tension you are neglecting between rest and repetition. More time together on the court makes for a crisper, sharper rotation. Merely expanding the rotation might address one side of the equation, the rest side, but the repetition side will suffer. There is some compromise position that has to be found each year, and Geno has mostly found it at 5+3 or even 5+2. And by rotation, I mean the players who get substantial minutes, i.e. >10 minutes.
Every year, when hopes run high for a healthy season, half the BY (including me) dreams of a deep rotation (10 or more) that presses and runs tirelessly for 40 minutes a game. But most years, somewhere in the middle of conference play, that dream gives way to a shorter, seasoned rotation that plays really sharp basketball.
Will the rotation in March be 5+3, or will Geno expand it to 5+4 or 5+5 this season? Whatever he does, it won’t be just based on counting minutes. It will be based on what combinations he thinks play well enough together to win a championship. And it takes most of a season to figure this out.