As an "old hare", I am used to parsers and recognize their value; but I have to admit I am quite concerned about the way they are used.
Often enough, I read about "optimal rotations" backed up by "undeniable parser evidence". Which then is used to make statements like
"chain X sucks, because chain Y does 3% more damage". Hey guys, this is not how it works.
When was the last time a boss fight allowed you to follow through with a static skill rotation? 1995? Ultima Online? Last time I checked,
every single DD in FF had a number of utility skills that are not directly tied to damage output. Just yesterday I had a lancer tell me that
"Feint sucks, because it is only 120 potency for 80 TP and disturbs my chain". I was at a loss. With a single attack, this guy was able to
reduce the damage I (PLD) receive from a raid boss by an incredible 20% for 20 seconds.* With no cooldown, just 80 TP. But he wouldn't,
because his parser said that "Feint sucks".
Now it is clear that not everyone in this game is an idiot, but sometimes I wonder whether the powers of Mr. Parser are not highly, highly
overestimated. They are definitely a good tool for estimating the effects of single stats on weapons or equipment (e.g.: how much extra
damage do I get for one point of STR). They are less efficient at estimating the trade-offs between two stats (e.g., is it better to invest in
STR or in VIT as a tank); and they completely fail at modeling the ever-changing conditions of a typical boss encounter in a 2013 MMO.
As such, their real-life (...) applicability (or "Ecological Validity") is inherently limited outside the pre-defined setting the respective tests are
run in. As such, a parser will not tell you whether your BLM profits more from additional INT or a little more HP to survive that nasty AOE. It
will also not be able to tell you if your skill at evading AOEs is high enough to warrant the investment in a glass-cannon build, when a more
moderate distribution of stats could save your ass even if you get hit.
There are countless other examples where a parser gives you a good idea about what to look for in general. But ultimately, the "best" stat
distribution or equipment depends on your skill, your playstyle, the encounter, and, often enough neglected, also your group composition.
A PLD doesn't normally need 5000 HP. But he will need 5000 HP if there is even a small possibility the WHM catches a lag spike.
In short: use parsers if you think you have to. It's actually quite fun to squeeze out that final 2%, even if the scenario you are assuming is
purely hypothetical (e.g., fighting against a static dummy). But use your brain to make decisions based on the overall situation, which includes
you, your equipment and role, but also the synergies between party members and specifics of the enemies you are likely to face.
After all, nature gave you those big heads for a reason. And that reason is not to slavishly follow when a parser states "Feint sucks".
Or when your government tells you that yet another war for oil in some faraway desert country is "right" and "justified", for that matter, hahaha! Okok, no politics here!
* Think!