ok... so reading that, apart from a bass focus and the existing plugins you're describing a HX stomp (the bigger one) or HX effects
Plus they have the added investment in UX, reliability and testing that they would have taken to get the product to the market...
So the question for me would be:
What is the extra bass specific functionality that you could do? and
What can these existing plugins do that existing guitar/bass multifx units can't?
the answers to that probably start to define what the hardware looks like and how you might expect the user to use it - and then it's about making it easy for people isn't it?