I noticed a subtle positive feedback loop in Dragon Quest IX last night. You have to be careful of these in long form games because they exacerbate over time.
Experience points are distributed by taking the defeated monster’s XP and dividing it by the weighted level of each character. This means if your party was a Level 3 Warrior, Level 2 Mage, Level 1 Priest and Level 4 Minstrel and the monster was 100 XP then the warrior would get 30 (100 * 3/[3+2+1+4]) XP, Mage 20, Priest 10 and Minstrel 40. The weakest characters get the least XP.
The problem with this is that the first time one character dies, the other characters get a relative XP boost and continue to get that boost for the rest of the game. Let’s say the priest in the above example keeps dying. He keeps getting a smaller and smaller share of the XP loot as the other party members take more of the pie, leveling up faster and hence getting more of the pie. While it is almost an accepted mechanic that there is no “catching up” in XP totals, usually the penalty is only for the time that character was out of commission and becomes moot by endgame. In the Dragon Quest example, since it applies to every single battle, the inequity gets larger and larger as the game goes on for mistakes that may have happened thirty game hours prior.
It’s not game-breaking by any means, but it makes it more difficult to go forward when one member of your party can get insta-killed and the others are shrugging it off. A simple thing like an XP formula can cause problems in the game dynamic if unchecked.