If you want a answer from the devs on whether or not knowing your dps numbers are important for clearing savage/extreme mode content well you already have one.

After having a record number of low clear numbers for the first tier of alexander, they released "stone sea sky" in patch 3.2 with the release of alexander midas and it's savage content. So they may have reservations about adding a parser but they still think you having the information is important/helpful for clearing the content (even if they aren't going to give you exact numbers and just tell you if pass/fail).

I am not gonna touch the "parser or not politics" with a 10 foot pole any deeper as I'll just leave it up to the devs and what they want as that is the sensible thing to do. I AM saying however that the devs seem to think dps numbers matter to clearing content as adding "stone sea sky" was a response to poor savage clear numbers. Personally I'd prefer a parser as it was what I had in Rift, WoW and other mmos but I'm not one to insist that FFXIV be like other games...even if I'd prefer it.