Crimson Longinus
Legend
So use the variant rest rules. Problem bloody solved! The variant rules are there for the reason, it's not the designer's fault if you refuse to use the tools provided.People don't play 6-8 encounter days though. Its a bunch of combat grinding that just doesn't play out organically without variant rest rules. The entire balance premise is flawed because most games aren't hack and slash dungeon crawls with inorganic hour long naps in enemy territory.
You're traveling through the wilderness - casters win without variant rest rules. You really think there's going to be 6-8 random encounters in a day? You have 2 months of downtime between adventures. Casters get narrative control through spells. Martials get... skill checks that the casters can also do.