Most classes are already proficient with unarmed strikes and improvised weapons. They're simple weapons after all. It seems to me that's just to make the feat usable for corner cases that aren't automatically proficient with simple weapons.
The real meat and potatoes is the bonus grapple attempt when using an improvised weapon or unarmed strike.
The extra unarmed damage die is okay, but neither here nor there.
EDIT: just a note to say I'm personally glad that unarmed strikes are not by default light weapons. Because if they were, that would create the situation of "dual wielding" fists. And the unarmed strike isn't intended to be any particular part of the body, but a generic action, of making an unarmed attack, whether with the fists, or a kick, or a head butt.
Same goes for any weapon strike. We don't need separate damage dice for pommel strikes, murder strokes, or thrusts. A longsword attack is an attack in which the longsword is a major component. The actual damage might come from point, edge, pommel, or fist to the throat. We shouldn't try to turn all those into discrete moves