I've been playing with the idea of including a page at the back of our player's handbook (or maybe our GM Guide) that talks about the core design fundamentals and why elements were designed a certain way. Another thought was including small 'tip' boxes on the side that is like "Word from the developer: this was designed this way because" (though less keen on this idea).

I was thinking doing this might help players and GMs further understand why rules are the way that they are. Pull back the curtain a bit to hopefully help better understand why mathematically the spellcasters do less damage than the martials, or why enemies get two turns per round of combat. I think this might help players also make better decisions in their character creation, or help new players better understand game mechanics. It could also further shed light on the type of game they're playing.

In my mind the best spot to put this is as the last page in the PHB so it doesn't get in the way of learning the rules, but players can come and read the core fundamentals that led our design approach if they so need. What do you think about this?