I did enjoy Roseanne, it was nice to have a show on where everything wasn't perfect. Not sure how they will handle the Dan being dead and the girls being with the opposite Healy brothers, but like others have said they may just ignore all of that and just rewrite history.
If they do rewrite history they may joke about it like they did when they brought the new Becky on. At the end of her first show they had the family watching Bewitched and they talked about how cheesy it was that they brought in a new Darren without explanation, like the audience wouldn't notice and then Sarah Chalke chimes in and says I always like the second Darren. Lecy Goranson would come back again and her first show back she walks into the kitchen and Roseanne says where have you been lol. Then when Sarah Chalke comes back again it was the episode where they go to Disney World and Roseanne says to her you picked a good week to be here. So they have dealt with obvious cast changes to the show with humor.