Would love to see a switch to prevent unrecoverable delete of junk mail. I have a lot of mail that lands there, and an accidental delete causes it to disappear forever.
I am thinking that if there is a lot of email landing in your Junk E-mail that you want to keep, maybe reviewing your junk mail settings will negate the need for recovering accidentally deleted junk. 
true, but consider that not all corporate email users are in control of overriding server behaviors and heuristics that determine junk.
Yes, I get your point. Did you know that deleted junk previously went to trash? I am not sure exactly when that changed, maybe it was with the release of the first version 7. I guess this feature is seen as an improvement.