I'll never forget First Look Alpha. Those feels will not get replaced anytime soon. I have high hopes for TTK and I know it'll be awesome especially with an awesome community.
I remember when I reached the cap at Level 8, still finding secrets like the giant Ogre being ?? And being scared going to him through the hive underground. Finding gear that was level 10+ and Blue and unable to ever equip it since we couldn't go passed Level 8. It was just so new and good.
I just wouldn't expect that much "new" since in the core of it all, it's Destiny that we've played. I'm excited as heck for the dynamic strikes and a 6 man raid that's bigger and better. Not to mention new subclasses and a story to tie things together. New PvP maps and modes. Tons of new weapons and gear and customizable features. New level cap and going away with light. It's really all epic.