Update - I created a new game in a downloaded town with all the expansions listed as needed. I created a guy + dog family. Then I opted out of Pets, Into the Future, Supernatural, Showtime, Late Night, and Island Paradise. When I tried to reload that game, it crashed.
I then created a family without pets in Hidden Springs. After opting out of the above 6 expansions, I reloaded save and it played fine. It even saved my settings. One hair changed, the refrigerator and stove changed, and probably some other minor things I didn't notice but overall I'm very pleased.
I then loaded my current game and it too played fine. A minor change here and there (furniture, clothes) and I noticed the showtime venues had been changed to empty community lots.
I realize I lose some towns and objects doing this but I have tons of CC and downloaded towns, both Store Content and 3rd party. I think the trade off of losing a few items vs dealing with paparazzi, vampires, pets, etc is well worth it for me.
If you have any questions, let me know.