If what I hear is true, then it sucks to be Nintendo. They'll probably lose out on a small amount of sales if it's only gamepad compatible for online mode. That's Nintendo trying to push out the word about a controller that is not much more than a gimmick. The pro controller is more than capable of being used, even if it doesn't have the touch screen. I'm pretty sure that it would be possible to make all of those functions work on a TV screen, just without the touch compatibility. They have done it in the past with other games, such as Wind Waker HD, so I really can't see why they would do something like this to Splatoon.
If Nintendo were smart, they would stop trying to prioritize the gamepad as much as they do now. Many people have broken gamepads, and they're extremely expensive to repair. You'd be almost better off just buying a refurbished Wii U from Nintendo.
One could hope that Nintendo adds compatibility for other controllers.