I had the same question. I think your blanching time would be increased if you boiled with husk on. It will take more time to raise the temperature of the corn kernal if the water has to seep thru the husks.

After seeing this thread, I did some web searching on blanching sweet corn. One article I read suggests you may not tell a difference - whether you blanch or not - if you consume the corn within 6 months. IF you store the sweet corn longer than that, you will tell a difference.