No Way. I've got mine ripped apart only because I ended up with a full monte, shell off resto. But I'm going to put the pink stuff right back in. Mine was actually in pretty good shape too. Unless you need to pull the interior panels and rip out the insulation, I dont see any good reason to do it. I believe Zep did an experiment thread, where he tried several different types of insulation and the pink stuff ranked up on top.
The floor pink stuff is another story. It is a horrible design that causes so much damage. I'm not putting anything back under the floor. Only because i'll have flooring over the subfloor, and I just dont think I need any. Plus I want the wood subfloor to be able to dry if & when it ever gets wet. I'm also in Florida, so I'm not worried about insulating from the cold anyway. Although, we'll see if the heat is something I'll wish I had floor insulation for...
If you are going to do your floor, the most popular method seems to be the foam board fastened underneath. Although I still believe that it should be attached so that it stands off the floor so that when it gets wet, its not sandwiched against foam that will not allow it to dry.... just my .02 cents.