They can rework all they want. Until all endgame activities allow for similar difficulty scaling, they wont be equal parts of endgame.
For gameplay, it should see the same rework as all other activities; more diversity, more random stuff having a chance to happen inside the dungeon to spice up the runs (like Butcher was a genuinely nice concept at release), different types of monsters and monster affixes that actually makes a difference in how you fight them, better map generation, and so on.