The way I have seen pro analysts attempt to do this is weigh the round and selection in the round the player was drafted, 2nd round pick 15 for example,
and them make an assessment as to his performanace after year 1,2 and 3.
A top five player should be getting Pro Bowl votes.
Players drafted in rounds 1 - 2 should all be starters.
Players drafted in round 3 should be contributing and seeing significant playing time.
And so on.
This is oversimplified as I state it.
We've had a lot of high 1st round picks to use, don't see any ProBowlers?