Destiny wouldn't work offline, IMHO it's perfectly fine as an online only title. If someone doesn't want to play it because if that, fine.. But who the hell isn't always online anymore?
I feel the 2nd could be even bigger than the first. People will B&M about how they hated the first all the way to wherever they're getting the 2nd, lol. I'd love to see Destiny more fleshed out.. But I feel an "offline" mode isn't needed. More so with how the game gets difficult. They could put in a great story mode and keep it online.. They also need to open up fire teams to at LEAST 4 people.. Six at most.