In-Game Parser.

[Nominous]

I call BS on this one. they are not now nor were they ever really a necessity. IF they really were the devs would have them in the game.
you can argue all the valid points you want in favor of parsers but this is not one of them.

It's possible to beat content without a parser, but it's putting self-imposed limits on yourself (and others) that don't need to be there. You don't need a speedometer in your car to know you're going too fast, or too slow on the freeway. Enjoy that speeding ticket though, when you thought you were doing okay, but didn't have an exact readout on your speed.

The same exact logic applies to end-game content. You don't need the meter there to have a general idea of if you're doing good or not. But having a parse on hand, while you're fighting, helps you make the necessary adjustments (using poison pots, or saving them if your raid DPS isn't on track) to actually beat a boss, instead of wipe to it. Do you get the point? It IS a necessity when it comes down to being a serious end-game player, and even as someone who's even taken a passing interest in getting into it.

Being educated about how well you're doing something is never a bad thing, and that's the root of why I don't think many pro-parser people understand the opposing arguments. It's not going to ruin anyone's fun (any more than it already does).