4e's reward system is magic items.
I agree with [MENTION=996]Tony Vargas[/MENTION] in having a different view of this. In 4e, you get XP for playing and (via the parcel system) get treasure for earning XP, so magic items aren't a reward either.
The "rewards" in 4e (as in, stuff that isn't a guaranteed result of playing the game, and which is obtained, or not, based on player decisions) are either in the fiction ("story rewards"), or else the thrill of victory in some particular encounter or other circumstance.
I'm not familiar with Traveller, is combat the primary mode of play? Is it how you advance your character?
Generally speaking, RPGs tend to have a heavy focus on character advancement, either through unlocking new abilities with levels/XP/etc., obtaining loot, or a combination of both. I would say that the "victory condition" for most such RPGs, in as much as there can be a single defined victory condition in such games, is such advancement. That's how you know you're "winning" at D&D
Classic Traveller doesn't have very much PC advancement in the D&D sense (which can be an issue for some players, including mine!). "Advancement" is building up your position in the fiction (more contacts, more NPCs in your employ, better starships, etc).
At the moment, as well as Traveller and 4e, I'm GMing Cortex+ Heroic and Burning Wheel games. In the former, PC progression is completely separate from in-fiction success: XPs (which can be spent on PC build elements) are earned by hitting "milestones" - particular events or actions - that are distinct for each PC (eg the berserker in our game earns 3 XP each time one of his allies rebukes him for his use of violence). There's no particular overlap between milestone triggers and the PCs actually achieving their campaign goals; and generally a Cortex+ Heroic PC doesn't need to
succeed at anything to earn XP (as per the example I just gave). In our campaign, the PCs are trying to find out the mystery of the northern lights, but so far have made only modest progress to that end despite earning plenty of XP.
Advancement in BW is a bit like RQ, but mostly doesn't require success on a check. And again, it's quite possible to be improving your PC yet "losing" in the sense of suffering story/campaign defeats.
I would say that classic/3E D&D is only one way to think about "rewards", and PC advancement, within a RPG.
When you're winning, your character gets stronger. Ergo, when your character gets stronger, you know you're winning. The optimal strategy, then, is whatever makes it easiest to get XP and/or loot fastest. This makes the means of XP distribution a very powerful tool in the DM's toolbox, allowing them to reward the modes of play they want to encourage. If you want a game where players attempt diplomacy first and resort to violence only when all attempts at nonviolent resolution have failed, simply give more XP for resolving conflicts without engaging in combat than you give for monsters slain, captured, or routed.
I prefer a different approach. I prefer for the mechanics to open up prospects of success in interesting ways, and then for the player/PC motivation to drive the choice of ways.
The interesting ways might be different in different systems - eg Traveller makes engaging with bureaucracy an important mode of success, but that isn't a bit part of most FRPGs.
Again, we are operating under different definitions of "gaming the system" here. You're using it to mean "breaking the system" or "playing in a way that is outside the designers' intent." I'm using it to mean "finding and exploiting the optimal strategy."
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Why is it strange to you to call that "power gaming?" because it was in accordance with Gygax's intended mode of play? If play has to go against design intent for it to be considered "power gaming," then the term is only useful for shaming modes of play you don't like.
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It's clear that we're speaking very different languages here. This has next to nothing to do with the point I'm trying to make.
I think that "power gaming" is a term that is generally used to describe (often, not always, pejoratively) an approach to play that the user of the term typically (not always) doesn't him-/herself adopt. I realise this is not your usage, but I personally just don't think it's worthwhile to try and rehabilitate the term.
Mostly this is because I personally don't find it a very useful term for analysis (but it's use can be interesting anthropological data, if one is trying to understand where another poster is coming from). I'm happy to distinguish between
good and
ordinary players. For instance, I'm not a good player of classic D&D (partly because I'm careless and partly because I'm impatient and probably for other reasons too that I'm not so good at diagnosing). Other people I know, and posters whose posts I read, are good at it - but I don't find it helpful to gloss their skill as "power gaming". It seems more informative just to say that they're good at classic D&D play.
As you noted, even the notion of "good" play can tend to dissolve under analysis for some RPGs: one of the players in my group has the mechanically strongest build in our 4e game; and is the best at advancing his PC in our BW play; but often doesn't have the biggest influence on the way the story unfolds. For instance, he failed to rescue his brother, in part because he made a series of choices aimed at giving him more checks to advance his PC even though they would make saving his brother harder.
We can then talk about players who are good at using mechanics (especially intricate ones, like 4e or BW), or who are good at playing the fiction and driving the story (not really a consideration in Gygaxian play, but significant in most of my games), or . . .