I'm mostly refurring to it's possibility in GW2 though. Yes it will be around, that is inevitable. But with the amount of options and the disappearance of set roles opens up the possibilies completely. There will be optimum builds, but instead of just one best for pvp and one best for pve now there will be many bests for different situations and different playstyles. Or at least I think and hope from what we have seen so far.
There were many bests in GW1, too; in PvE, everything was predictable, but there was an optimum way to handle every individual task, and the optimum was different for every task. In PvP, there wasn't anything even close to a 'best' build until the game got flooded with so many skills and classes that balancing became Sisyphean, barring occasional, temporary cases of clear imbalance (eg. The original version of the Fragility/Virulence harrasser - although this was compounded by the fact that in those days, 8v8 at the flag stand was the normal, accepted way to play the game).
The strength that GW2 has that GW1 lacked is that there's no real way to make a
bad character in GW2. The skill build options are quite limited, and the effects of most traits are relatively minor. The minimum level of effectiveness that you can give your character is still high enough that, even if you have, objectively, the worst possible character build for a given situation, the limiting factor for most players is still going to be how well they can actually play the game, and a good player with that bad build is still going to outperform a bad player who is using what is, objectively, the best possible character build for that same situation. Some of this is definitely due to GW2's increased suite of universal, build-independent, skill-based options like dodging, but a
lot of it simply comes down to the fact that there's less meaningful variation between two GW2 builds than two GW1 builds. You really can't fuck up and end up carrying a bunch of hump skills into a fight - but you also can't do anything different with your chosen weapons from any other Warrior with the same weapons, aside from trait selection (the effects of which are relatively muted, compared to the colourful differences between skills in GW1).
Make no mistake - Guild Wars 2 is going to be
far less mechanically complex (which is
not to say, however, that it will have less
depth) than Guild Wars 1, and that
closes off possibilities. The trade-off is that it's closing off a
far greater number of
bad possibilities than
good possibilities - and the gamble is that they're going to be able to make up for that loss of flavour by introducing new mechanics to compensate, like cross-profession skills and dodges.