Original Destiny was less than 30 missions, Destiny confirmed to have 80+ at release.
Hopefully they are actual missions too, not just
- Complete mission featuring the normal voice acting leading to story progression
- Follow up that mission with 3-4 more "missions" getting one more piece of the puzzle! featuring a minimal story progression of "we are going back, hopefully we find item X", making it little different than just running the same mission multiple times.
I remember that was one of my biggest disappointments from the patrol missions in Destiny. IE: Exploring the moon the first time and finding the way down. It felt huge and it kept going down. I was like "ohhh, I wonder if I find a boss or something." Found the two level 10 yellow mobs that I spent nearly an hour killing, to find... nothing. Locked door. Go further down. Locked doors. I remember it being so strange that nothing seemed to be there. Even went back later because I thought it was just me missing things or that maybe someone had cleared things ahead of me. I was naive and just thought... it is so big. Something must be there! Rare spawn or ... something.
Wasn't until later I learned how pointless it was to explore. Basically no point in going anywhere that didn't have a mission to tell you to go there. Closest being driving around the map hoping for one of the "events" to spawn.
I enjoyed the rest of the game. Played all story content with a friend and it was fun, but never played more than it. Didn't grind or do much of pvp.
My biggest hope for Destiny 2 is that they add more to the game than just do 30 (now 80) missions of "go there do exactly that in the fastest manner possible". Which I think they have as I saw that one video where they talked about things like caves now having the chance to lead to separate dungeon instances with things like mini bosses, jumping puzzles and the likes. So hopefully a bit more incentive to explore and find things not tied to your active mission.