Can you fix a class (or subclass) with one single change?

[Specter]

How about, "You can recover one level of exhaustion every short rest."

You still have to deal with the consequences of Frenzy, but they don't last as long. This also gives Barbarians a single short rest resource to play with.

You'd still have to specify Frenzy echaustion, otherwise such a character wouldnever syarve or freeze to death.