The problem with partitions and current rollback is that it doesn't actually work. What actually happens is that your data sitting on a separate partition from the system is automatically converted to whatever newer incompatible format has been shoved into the update with no thought to rollback.
No. I don't trust updates to working production systems. I already have to duplicate everything I use to work around broken design. The fault is with changing what works. If it works, don't break it until the world moves to less hackish approaches to software platform consistency.