As we all know at this point, BLU is to be locked out of hefty portions of content when introduced. When explaining why, one of the reasons provided was -
to avoid toxicity by party members if the BLU in question was missing specific monster skills.
While I fully believe this particular concern could've been alleviated through design, I agree with the underlying logic. Sadly, BLU isn't the only place where such things are possible, and I therefore humbly beseech the dev team to reconsider other aspects of the game in order to avoid similar conflicts.
My examples and suggestions:
1. Lock 30+ duties behind jobs.
You cannot partake in the duty unless you have the relevant Soul Crystal equipped.
2. Lock ARR and HW duties behind the completion of relevant job quests.
No more 35+ WHMs without regen.
3. Lock 70+ duties behind the completion of the relevant level 70 job quest.
Not only are you missing out on skills that depending on job make or break your kit, you're also missing out on gear.
On release, the best gear available before facing Shinryu was the ilvl 300 gear from Ala Mhigo, but no one was going to farm that place before taking on the trial. Therefore, the best available was the 290 job sets which many people didn't have. There was no guarantee they had full Castrum Abania sets either, so for most players, the 290 sets were a noticable upgrade. Lacking that, people died to unavoidable damage.
People not doing their level 70 job quests was one of the reasons why Shinryu was nigh-immortal for as long as he was.
4. Lock leveling dungeons behind a minimum ilvl.
Like how a BLU can't adequately perform without their skills, other classes can't perform without proper gear. No one wants to see ilvl 90 gear on the tank in the Vault.
People looking to bypass these restrictions should be allowed to do so with pre-formed parties, while locked out of the duty roulettes. Directly queue for duties.
Please feel free to offer feedback and additional suggestions!
EDIT:
5. Change the ilvl weight so right side gear matters less than left-side gear (at least for non-tanks, tanks have more vit on everything).
Tying in with #3, part of the problem in Shinryu was not enough vitality on people. Vitality comes from left side gear. Therefore, it doesn't matter how far ahead you can pull your ilvl if you buy the one crafted ring - you'll still die to the first unavoidable attack.