I made a similar suggestion here.
https://forum.muhro.eu/d/3309-remove-instances-cooldown
Of course, i used to only play one character but LoF and the fact we now MUST farm a lot of instances in order to keep up with some little progress with HoL gear, I had to make 14 clones in an account to farm it (still in leveling progress, only 3 of them are 240, not even 250 yet).
I'll keep saying, 15 instances PER MASTER ACCOUNT should be enough.
Of course people made investments in time and zeny (skip episode tickets) but i feel it's really dumb we have to create clones over and over in order to get a shot in the current meta.
I have no problem with people who spam instances, since it was only an option to grind them for mats. Now though, it is required. You no longer can farm a dungeon whenever you feel like for how much time you want (referring to depth 1 and 2 equipments), you need materials locked behind a daily wall that's easily skippable if you create another character. And another. And another.
We can now either create 1230985 clones or hope we get a 6% enchant in 3 years.
Of course i'm exaggerating, but it's frustrating.
I hope you can excuse for my rampage, not sure if i expressed it civil enough. Just wanted to add my point of view and context.