Well first off, SI is not OP. Statistically, considering how abundant they are, people are much more likely to perceive them as OP because they are getting killed by them most frequently... not to mention that lightning is the most visible effect on the battlefield and thus will stand out more in someone's mind. The perception that the SI is OP is false though.
I certainly did not say SI is OP. I merely stated that they are far far too many of them, and the only way BW is going to even out the class/population is by nerfing certain overpopulated classes. Simple, no ?
And don't kid yourself, that WILL happen.