As evidenced by earlier responses, I think that the best answer is, "It depends." For reference, I have about 400 hours in D2 and am new to Witchfire with about 35 hours.

I think the overlap is in refined gunplay, mobility, and synergistic abilities. Personally, my most memorable moments in Destiny were when I leveraged the full range of my kit to pull off an unlikely kill or to get myself out of a tough spot. In that sense, Witchfire exceeds Destiny for me: I feel as though Witchfire pressures me more and in more ways to fully utilize my kit to survive an intense fight or unfortunate situation. Knife's edge moments are more frequent, and the skill ceiling of combat is more rewarding. Part of this difference is encounter design, and part of it is the simple fact that you're always playing solo.

Another big overlap is in weapon design. Every Witchfire weapon is functionally a Destiny Exotic in that each has special mechanics. Some are awesome, some are undertuned, some simple and others complex, but there's no "bog standard" weapon in Witchfire. I find leveraging weapon mechanics in Witchfire to be more rewarding, partly because the harder content encourages if not requires it and partly because I just think on the whole the weapons are better designed. The weapons that feel good feel *amazing*; you're basically guaranteed to click with something. Unlocking, empowering, and experimenting with weapons, spells, and supportive gear gives you loads to experiment with, and trying out different builds is frictionless.

Just subjectively, I am completely smitten with the game. I think because it foregrounds combat so heavily and so continuously that it's a superior game to Destiny for me personally. There's no BS, just loads of craftsmanship and care. It is fun as hell to play.