Prior to this change, grapple was junk except for grapple optimized PCs.
On grapple optimized PCs, it was crazy good. You bypassed saves, legendary resists, and got to add twice your proficiency to your attack and defence checks. The enemy eventually ended up prone, granting advantage to all of your allies attacks and disadvantage on all of its attacks. To break out, it had to burn its action.
On a high-CR enemy, you trade 2 attacks for it having a chance to break out as an action, and not a good chance, plus crippling the foe.
It was bad enough that 5e monsters had to start designing themselves to avoid the problem (having get out of grapple cards), and PC size had to be limited (as one defence for monsters was simply being too big to grapple). Once players could reach huge, they could grapple anything; so that had to be limited to T4 high-investment builds.
On grapple optimized PCs, it was crazy good. You bypassed saves, legendary resists, and got to add twice your proficiency to your attack and defence checks. The enemy eventually ended up prone, granting advantage to all of your allies attacks and disadvantage on all of its attacks. To break out, it had to burn its action.
On a high-CR enemy, you trade 2 attacks for it having a chance to break out as an action, and not a good chance, plus crippling the foe.
It was bad enough that 5e monsters had to start designing themselves to avoid the problem (having get out of grapple cards), and PC size had to be limited (as one defence for monsters was simply being too big to grapple). Once players could reach huge, they could grapple anything; so that had to be limited to T4 high-investment builds.