I think Hayward is well worth the max, but I agree that Crowder is even more valuable.
On the open market I believe that each player's value, for the upcoming year, would be something like:
Crowder: $20m ($13m above his $7m/yr salary)
Hayward: $40m ($10m above his $30m/yr salary)
Brown: $10m ($5m above his $5m/yr salary)
Note that this understates Brown's true value since he will improve over the next several years, I'm just trying to put a number on each player's production for next year.
If we have to dump Crowder to make room for Hayward, this will be a net negative move.