Destiny was a game that got mixed reviews. While it was certainly fun with your mates, it lacked the overal content of what an MMO should have in the box. Anyway, it has been said that Destiny 2, should such a thing exist (as it hasn't been confirmed by Activision right now) will not release til much later than 2016.
The studio first planned an 2013 release for the original title and didn't send it out til 2014. This could be a reason for the delay, remember, it isn't actually confirmed yet.