[DEV Question] Why is this allowed?

[Nestama]

It can still be the most important piece of gear but right now it's practically the only piece that matters and that's a problem.

No... you'd still need decent gear so you could survive raid-wide AoE's (VIT) and have decent Secondary Stats (my BLM has 1248 Spell Speed. Mostly thanks to the gear I have + materia).

I also said level. Not ilvl. You should not be able to enter a Level 60 Duty with a Level 50 weapon (you can even buy Level 60 weapons from the Helix vendors).