Absolutely. GamePad is essential to gaming for me now. It may not be revolutionary, but it has been evolutionary for me. If the next console lacks it, I'll be so sad. People really don't appreciate how much it streamlines things. Is it perfect? No, but it's a good thing.
I hate going through cumbersome menus on the other platforms now. Playing GTA V after so long on the Wii U felt like a step back.
Having it be optional in future platforms is the way forward, and having current GamePads be compatible eases the expense for the ~10 million people with a Wii U already. It means developers may not use it, which sucks, but it shall be here.