For myself, I'm pro and anti when it comes to the use of parsers. On the one hand, I don't like having someone put a metaphorical gun to my head, constantly monitoring my performance like Big Brother and ready to pass judgement on me or anyone else who lacks. So many elitests use parsers as a way to weed out the weak rather than use it as a tool to address a problem and fix it (ie, suggesting other rotations or discussing specific gears to equip instead). That's kinda why i'm happy SE is very on the fence with parsers. With the exclusion of parsers, every player has a chance to run dungeons or instances without the worry of Big Brother watching them.
On the other hand... players really should know how well their DPS is. Coil (non-nerfed, lol) has always been my reality check. There, I know I got this-and-that amount of time to kill an add. If it remains alive, it means I am lacking in the DPS department. Sadly, this game doesn't provide gamers their proper rotations, only a few suggestions given during their quests. It's left to the gamer to figure the rest out. It wasn't until another BLM in Titan ex put me aside and told me how bad my rotations were bad and what to do instead that i finally figured out how to make the most of my BLM. I also researched more about my role online and listened to other tips from fellow casters. Unfortuantely, a good chunk of players don't do this. And it's evident when they are dying constantly in Titan ex prior to heart phase (without echo) with their level 110 gear. They're depending on their gear to save them and ignoring proper rotations and fight mechanics.
It doesn't surprise me at all that many people waited until t5, Leviathan, and Thornmarch got the echo (aka nerfed) buff to take on those fights. Sure, the echo gives every player a chance to win a difficult fight. But it also conceals how much damage they really possess or lack. It's why, in this regard, having a form of to measure damage output is important. So long as SE makes it difficult to gauge DPS output, people will resort to parsers to help them win the fight. in my opinion, it's not cheating, but recognizing the issue behind party wipes. PArses give no more advantage than Echo does. In the end, the party will need to still follow game mechanics and dish out the hurt to win the fight.