If you are expecting 2.1 to keep you occupied when you already have full/near full iLVL90 gear, you're going to have a bad time. From the sound of it, the only "new endgame" will be the extreme mode primals, and only if they serve a real purpose, like the theorized relic+2 (wouldn't count on it)

Crystal tower isn't going to give gear better than coil, so there will not be much point of running it other than it will be Dfed for skipping DL tome farming.