This is an oft overlooked but very important distinction, and part of my original premise in that what one the system (or the DM) awards XP for will have a motivating impact on play. And, in fact, will define what is being called "player skill" to a large degree.
In 1E, most of your XP came from treasure acquired (aside: which was also quickly unacquired, with upkeep and training costs and keeping henchmenr and all that). Monsters, by and large, weren't worth much and therefore even if you only got XP for defeating them (as opposed to evading them or whatever) it still wasn't a big loss. Creating a distraction so the ogres would all go rushing down the hall so you could loot their lair was a perfectly viable strategy. In many cases, however, the creatures with the greatest potential reward -- the best treasure types -- were also the toughest and least likely to be tricked or sidestepped. On top of it all, some truly dangerous monsters didn't offer much treasure at all, and these became even more frightening to the PCs because there was risk with little reward. Beware the random encounter! Traps didn't give XP in and of themselves -- it was what was in the chest that was valuable. So, in 1E, "player skill" could be said to include techniques used to avoid encounters entirely and still get to the loot.
