4) I hate the diplomacy skill.
My issues with Diplomacy begin with my issue with most skills in d20, in particular the social skills - between ability modifiers, skill ranks, feats, class abilities, and magic, equipment, or racial bonuses, characters can quickly trivialize the DCs in the rules-as-written.
That said, from what I've read there are some common problems which arise from how referees interpret the skill. First, some referees seem to treat Diplomacy like
charm person, but Diplomacy is not a magical compulsion - moving a non-player character's attitude to "Helpful" shouldn't make them a thrall to the adventurer. The non-player character may "take risks" to aid or protect, but taking risks is not without reasonable limits or conditions. It also requires an environment conducive to making an appeal or argument - combat and similarly situations should be right out - and it requires a willing, undistracted listener.
Second, one of those limits on aid received by the Diplomacy skill is that many checks should be treated as opposed. A non-player character may have a "Helpful" attitude toward the adventurers' enemies, and gaining a "Helpful" attitude result doesn't automatically change this. The aid or protection a non-player character may give in these instances may be simply to remain neutral, or to offer to seek reconciliation.
Third and last, from what I've read a number of referees fail to consider the caveats contained in the Diplomacy rules. For example, there is a time component: "Changing others’ attitudes with Diplomacy generally takes
at least 1 full minute (10 consecutive full-round actions).
In some situations, this time requirement may greatly increase" (d20 SRD) and "Diplomacy is
at least a full-round action.
The GM may determine that some negotiations require a longer period of time" (d20
Modern SRD). I prefer the
Modern phrasing here because it doesn't include the "rushed" full-round check in the original SRD, which with massive bonuses can result in a change from "Hostile" to "Helpful" in six seconds, and by leaving the time period required to use the skill to the referee's discretion, to my mind the
Modern rules encourage roleplaying the argument before making the skill check. Moreover, because the skill is not a magical or psionic compulsion, the skill requires a willing listener and the absence of distractions.
I don't think the Diplomacy skill is any worse than the other social skills in d20 games; I think it suffers from the same problem of bonus bloat that plagues the rest of the game, but I also think there are limitations on its use. In my experience, social skills don't detract from roleplaying, as long as they are used to resolve the results of roleplaying, rather than as a substitute for roleplaying.