I believe the pro tennis tour is too long. But remember, it used to be a year long sport, with no off season at all!! Go back to the 1970s and early 1980s. There was a tournament every week! The season ending events couldn't even fit in the calendar year, so they were held in January, culminating the previous year's tour! And the very next week the new tour would start up again. So in some respects, today's players have it easy.
And it's easy for fans to say the season isn't too long.
It'll never happen in my lifetime, unless they offer me job as tennis commissioner, but pro tennis needs a more intelligent schedule, to maximize the potential it has.
I don't know if the complaints you hear are sour grapes, but I think some of the complaints are rather empty when the same ones calling for a shorter season are seen planning and playing exos in the off season! Don't know if I agree that players should just take time off during the season. There are rest weeks built into the season already. Some players don't manage their on schedules well enough. And there is too much greed on the part of tournament directors, agents, TV folks, and players themselves when it comes to tournaments and commitments.