When Armorcraft Judge enters the battlefield, draw a card for each creature you control with a +1/+1 counter on it.
Armorcraft Judge's ability counts the number of creatures, not the number of counters. A creature with more than one +1/+1 counter won't cause you to draw more than one card.
The number of creatures you control with +1/+1 counters on them is counted only as Armorcraft Judge's triggered ability resolves. Players may respond to the triggered ability by trying to change that number.