My question is what would happen if you applied the same method of analysis MJ is using here to, say, a Recon Specialist on a Bounty Hunter. I doubt it would be as valuable as the Emperor, but I suspect you'd find that according to this method a lot of upgrades are going to be very valuable.
Conversely, if you applied the same method to a PTL on Sooner Fel that you were actively blocking as a game strategy, it would make PTL on Soontir look like a bad card.
Which inherently, supports my previous statement saying that there are too many factors to quantify certain upgrades.