Caden, that is a rather stupid statement. If a civ is overpowered, that means it can't be countered or adapted to - period. That's the very definition of overpowered.
If Set *isn't* patched, then it will be impossible to play any civ except Set above 1900 - in fact, rendering the game unplayable if you are too good at it. In essence, you penalize ES's most addicted customers.
Second, there is another thing concerning balance - balance issues tend to manifest themself at the top first; however, after a while, they tend to spread downwards through the ratings - which means that if the 1900 level is dominated by Set today, then the 1800 level will be similarly dominated after a while, then 1700 after a longer period, etc - people tend to get better as the game matures, and competition hardens, thus the practice required to acquire a certain rating goes ever upwards.
Finally, Set isn't as micro-intensive as people here make it out to be - all it really requires is a basic knowledge of how waypoints work; however, I've seen that knowledge absent in even 1900+ level players.
The bottom line is - eventually, the knowledge of how to use the powered-up aspects of Set will trickle down through the ratings and be abused by everyone and their cat. Taking the attitude that "Set is only imbalanced for the elite players, and they are arrogant bastards who should shut up and let us newbs and inters play the game like it is" is viewing how games evolve through very rosy-tinted glasses.