I sometimes wonder if we are hyping TTK too much. It is an expansion, one patrol area, a couple strikes, a raid and some PvP maps. Those going in expecting a new game are going to be let down again. Can't wait for it, I'll love it, but it's a mixture between added content, remixed content, and quality of life improvements. Not a new game.
Yes, at least there will be a ton of new mechanic changes like the way light and gear and levels are used to make it feel fresh, but the content seems like we're going to need more in maybe the next 3 to 4 months already.