What are people's thoughts on the differences?
I really don't think the difference is all that necessary. (although one must assume rigorous playtesting is what brought about the two format cards)
Basically, a BR with those surges has a 91% chance of getting 1 or more damage through a Black Dice and 82% chance of getting 1 of more damage through a White Dice.
Comparatively, with the -1 Damage from Crowd Control (optional obviously), those stats fall to 73% for 1+ vs Black and 76% for 1+ vs White.
Granted the 1 Strain has an entirely different meaning in Skirmish vs Campaign.
As anyone who has used the Regular Gammorreans will tell you, a -1 damage on attack is pretty debilitating (on 2 Reds at that, let alone Red Blue)
If protecting the Rebels from the strain gain was so important, why not have simply have both versions do what the Campaign version does? Or is strain in skirmish so weak it cannot handle the chance reduction?)