Fast healing gets obsolete quickly. Once you get geared up, you don’t take so much chip damage and can afford longer downtime. Not to mention that health stat (hidden, governs regeneration) is currently unbalanced and easy to increase later on.
Fast learner is good on a typical character in a typical world, but it is quite bad in dangerous worlds with fast evolution and/or fast zombies.
Robust genetics’ overpoweredness is based on mutation system, which hasn’t been touched for a long while. It only affects a small percentage of characters, so it didn’t get good balancing feedback.