I really hate the idea of aging. I’d rather the X-Com approach be used, where your elite veterans are your elite veterans until death take them. I want losing my elite mercs to be memorable, not a depressing inevitability due to the ceaseless passage of time eventually making them weak, incompetent old men.
Similarly, the idea of progressive, permanent morale/resolve damage is not appealing. I really think it kills the satsifaction inherent in an RPG game about building a merc unit to have your most experienced mercs suffer cumulative penalties and degradation. In my ideal low fantasy medieval setting, the battle-hardened mercenaries are not a bunch of cowardly old cripples who jump at shadows. They’re steely, determined hardasses who don’t flinch when an orc berserker comes barreling down at them. As for the Immoral and Carefree bits, how about we just assume that everyone willing to kill for money is either Immoral or Carefree and thus the lack of remorse at being a mercenary is automatic and not something that needs an in-game representation?