By your definition the iPad 1 was not a first gen product but a continuation of the iPod Touch and iPhone.Indeed it isn't a firsr Gen product, it's a continuation of the iPad air. Problem is the bigger screen has brought to light ( and I think even the air suffers this problem) the fact apple wastes to much screen size and power with a dumb OS that is far too simple.
There's too much new technology and differences in the iPad Pro to NOT consider it a first gen product.