RC, I've got in mind a few things. One is, as you note, the XP system. The second is that combat scales automatically with level (BAB, saves, damage to an extent via spells/feats) in a way that skill bonuses don't, meaning that there are two rather mechanically divergent action resolution contexts that the rules (at least from the original 3E DMG, which is the one I know) don't say much about how to integrate.
The third thing, related to the second, is that the skill rules for 3E tend towards the gritty (for example, there's no way to hit the DCs for the quasi-supernatural balance checks in the Epic Handbook without using magical enhancements) whereas the combat rules tend towards the gonzo (eg the classic fighter-who-can-fall-200-feet-without-dying).
I think all of this combines to create a greater likelihood, in 3E than (for example) either 1st ed AD&D or 4e, of a game in which the non-combat skill-oriented aspect of play becomes almost a separate game from the combat part.
And to link this back to the original thread topic - I think this also contributes to the martial-vs-magic problem that some see. Outside of combat, martial/mortal protagonists are stuck with a rather gritty and realism-bound skill system, while spellcasters get a gonzo, no-holds-barred and no-chance-of-failure spell system. And at least as I recall it, most of the advice in the DMG about mid-to-higher level play, as well as from the major designers of the game, is to adjust the game to accomodate those magical abilities (eg don't make the mystery the plot point, but rather the proving of the conclusion) rather than to adjust the game to make room for the gritty skill system.
This is what I mean when I say that the guidelines for encounter- and scenario-design don't support making skill-oriented issues a core part of the game.
A final qualification - at low levels, the points I've made will tend not to show up. The combat and magic is less gonzo, the differentials in skill bonuses won't generally have become so salient (in part because there is less magic and stat bonuses are still a bigger contributor to the overall bonus), and it is therefore probably easier to integrate skill checks into tactical encounter design in a way that makes the XP issue go away somewhat.
Personally, if I wanted to play an E6 style game I'd probably use Runequest, but I can certainly see why some people favour it as an approach to 3E. It's not just the flavour, but it really does avoid some of (what at least I regard as) mechanical problems emerging.
The third thing, related to the second, is that the skill rules for 3E tend towards the gritty (for example, there's no way to hit the DCs for the quasi-supernatural balance checks in the Epic Handbook without using magical enhancements) whereas the combat rules tend towards the gonzo (eg the classic fighter-who-can-fall-200-feet-without-dying).
I think all of this combines to create a greater likelihood, in 3E than (for example) either 1st ed AD&D or 4e, of a game in which the non-combat skill-oriented aspect of play becomes almost a separate game from the combat part.
And to link this back to the original thread topic - I think this also contributes to the martial-vs-magic problem that some see. Outside of combat, martial/mortal protagonists are stuck with a rather gritty and realism-bound skill system, while spellcasters get a gonzo, no-holds-barred and no-chance-of-failure spell system. And at least as I recall it, most of the advice in the DMG about mid-to-higher level play, as well as from the major designers of the game, is to adjust the game to accomodate those magical abilities (eg don't make the mystery the plot point, but rather the proving of the conclusion) rather than to adjust the game to make room for the gritty skill system.
This is what I mean when I say that the guidelines for encounter- and scenario-design don't support making skill-oriented issues a core part of the game.
A final qualification - at low levels, the points I've made will tend not to show up. The combat and magic is less gonzo, the differentials in skill bonuses won't generally have become so salient (in part because there is less magic and stat bonuses are still a bigger contributor to the overall bonus), and it is therefore probably easier to integrate skill checks into tactical encounter design in a way that makes the XP issue go away somewhat.
Personally, if I wanted to play an E6 style game I'd probably use Runequest, but I can certainly see why some people favour it as an approach to 3E. It's not just the flavour, but it really does avoid some of (what at least I regard as) mechanical problems emerging.