FormerlyHemlock
Hero
I think it depends largely on things like your players' openness to metagame currency (including XP BTW). The primary problems IMO with the GURPS disadvantage system are that:I mostly agree. I think there are two kinds of disadvantages, broadly speaking: numerical and narrative. Numerical disadvantages are basically just the reverse of numerical advantages – things like weak will, lowered move, etc. I think it's fair to give points back for those. Narrative advantages would be things like phobias, curiosity, various handicaps or social issues, and it's better to give some kind of metacurrency as a "reward" when those are triggered.
1.) Point accounting: points from disadvantages are fungible, and the praxis of imposing a numeric cap on total disadvantages is wrongheaded; and
2.) Bad rules: Many disadvantages are un-roleplayable as written because they require you to act in insane ways regardless of context.
Dungeon Fantasy RPG improves on #1 to some extent by just baking certain concept-appropriate disadvantages into every character profession (i.e. class), spending the points for you in advance, and providing a suggested list of other disadvantages to round out your mandatory -50 point total. In some ways I might prefer a system where opting into certain advantages (like Combat Reflexes) can be "paid for" partly by opting into certain thematically related disadvantages (like Paranoia, One Eye, or Social Stigma: Criminal Record) and you have a cap on total mental disadvantages rather than all disadvantages... but the DFRPG system is good enough to be playable when it comes to chargen.
Not so with the actual mental disadvantage rules however, which are the same in DFRPG as in GURPS. The essence of the problem is that if you take a disadvantage with a self-control roll, such as Greed, you are required to reduce yourself to a one-dimensional caricature whenever you fail a self-control roll. If you're Greedy at more than the 1-point quirk level, then if someone offers you $100 to sell your children into slavery, and you roll poorly, you will do "whatever it takes to get the payoff, however illegal or ill-advised" even if it requires you to betray common sense and all your values, such as actually selling your kids into slavery for petty cash! The self-control roll rule is context-free and too simplistic. In practice nobody runs these rules as written, which is proof that they're broken.
A good fix that doesn't require metagame currencies is to just give the player a strong incentive to roleplay the given trait (such as a temporary but sizeable penalty to success rolls, from the distraction and guilt of secretly wishing you had that $100, after failing the self control roll but not selling your kids). That way players can still avoid irrational, insane behavior, and roleplaying remains coherent.