Oh, don't get me wrong. I'm seriously looking forward to it. The new features are going to be killer. It's just that we're very likely going to lose quite a lot.
Back when Island Living came out and all the bathtubs broke because of the mermaid thing, we lost quite a number of them because the CC creators released them ages ago and then abandoned them. I had quite a few that broke and were never re-released for the update. In fact, I think I only have one that was actually updated. I had to go find a new series that were created for the pack. This is likely going to happen again, only with a lot more things. Most of my lots on all of my worlds will break because of broken CC showers, tubs, and other electronics.
I'm really not looking forward to losing half my CC objects.
Mods will just take time. If any of my own break, I'm confident I'll be able to fix them within a day. Others aren't as timely or have a lot more to fix than I do.