Stoneskin was not great in HW, it was already a step out of the door. Benison is the new mitigation for WHM and that's okay.

Five slots is fine, just protect is a bit of a hazy situation as YoshiP did want to remove it but got some flack internally because of how can you have a FF game without it. If that skill was just passive, threads like this wouldn't exist. More or less every fight is a different. Savage is the same way, you really don't use the same five skills in every floor. Sooner or later they will probably throw a mechanic where Heavy (Break) could be useful again. You have to remember they did an analysis on every skill that every role should have.

Some may think some skills don't have value, but they also haven't done every content available in the game (O4S Surecast), or know that there was old content that actually had use for some of the skills when they were relevant (Heavy in A3S/Turn 5. Now that healers lost DPS skills that had the heavy trait).