In my oldest D2:ED save I had already cleared out the goblins and the primordial cave up to the door opened by the seeds quest. At level 23, the level 21 imps along the path to the harbour were giving me 830 exp, so that would be about 1050 if I were level 21.
If the experience scaling with level difference is the same as it was
in D2:ED, there is a 21% drop in experience if you are 2 levels below your opponent, and a 63% drop if you are 3 level above, but that isn't nearly enough to explain the drop in experience you had with the goblins, though.
