Back on topic, I've made a few posts on this subject in the past:

http://forum.square-enix.com/ffxiv/t...parser-problem

http://forum.square-enix.com/ffxiv/t...Ms-hate-her%21

I honestly don't think we will get an out right in-game parser at this stage without a very major u-turn from Yoshida. A party wide one is just going to light a fire under the populace and whilst I personally don't think there's any reason not to have an optional self only private parser of sorts in the game that's usable in proper content. Again that's a highly sensitive subject for some.

IMHO my favourite approach now would be a blend of the above two suggestions I made:

Anonymously log every last player's potency per second across the run whilst in instanced content. Use that to build an approximate series of rankings similar to the logs percentiles for each job. Take that and score a player at the end of the duty. Nothing precise or offensive, simply S-A-B-C-D-E-F or such.

It'd be effortless to implement, completely gear agnostic and most importantly, it'd be a good subtle way to give feed back as to how well or badly a player might be performing. Frankly I wouldn't even put achievements on it to minimise the agro potential of it.