While I wouldn't go as far as calling Destiny and Phantasy Star Online the same game, this lovely chart from Redditor KytorIndustries makes a compelling argument that they pretty much are.
Fans of Sega's Phantasy Star Online series have been making the comparison since Destiny was initially announced, amused that the cool new game everyone was excited about was a lot like the cool old game they'd been playing for years. The view might be different, but the feeling's the same.
Or it was. At this point Phantasy Star Online 2 has four character races and four classes. We'll see if Destiny catches up by the time it's finished.