You wouldn't invite a level 40 player to fight Ifrit.
No but apparently you can invite a Level 46 WHM in FFXI to run a Windurst Mission marathon and get Rank 10 after deleveling to 42 in the process no problem.
True story btw. ;)
But relating to FFXIV. I will state this now... if I know someone is a skilled player, I don't care if they want to run Ifrit in the reindeer outfit from 1.0. If I don't I might personally go over their gear to see what they have equipped what kind of materia they may/may not be using...however I am not going to rely EVER on some random number and judge someone by it.
Gear does NOT mean you are a better player. I have out parsed people in 1.0 as MNK and BLM while having inferior gear, because I had better timing/understanding of mechanics/understanding of my class skills/knowledge of mob abilities/etc/etc. And I am sure the same will still be the case for FFXIV.
That also doesn't mean that gear means nothing. Sometimes a fight comes along that becomes much easier with certain gear. In this situation, it is okay, imo, to say, "Hey you need this gear, bro. It will be way too rough without it..."