Optimization is so broad its no wonder they have no idea what you mean. If you mean the ui its been improved so much over the past 3 years from its laggy release state. If you mean general dungeons they run fine if you aren't using a toaster. Load stutter when entering an area for the first time is just the way the game is programmed and you gotta live with it.
They do listen to feedback but only from kr. For example glaive lynn was going to get an utterly forgettable long awaited buff but the kr lynn players rallied to get them to buff her for real and they listened. From this point yes they do have character balances.
Counterforce was a bad idea i agree but you can get literally free +15 lv90 belt and earrings upgrade them a bit maybe build a dulla ring and be perfectly capable in lv100. Ya it takes some effort but why should it not.
Agree that 8 man should be an option or at least make it 6 man instead. 4 doesn't feel raidy enough.
QB requirements are like the bare miniumum if you can't reach them the boss will just get tickled by you. If you wanna enter with tickle stats play with your friends in a custom party cuz no one likes to deal with 0 damage people in a "quick" battle.
New players leave for a multitude of reasons. New games might appeal to them more, the combat isn't for them, the fact you have to work to get anywhere, important info is not presented in game like money making tips.
I do give them some respect for not falling to the whims of the community every time tho. The community doesn't always know best.
(ya support doesn't play the game hence they couldn't answer your question best to ask that in the discord)
The only reason they don't is greed not that they can't as seen with the vindicator box before that went indefinitely until it was pulled. They want you to ideally whale on every gacha regardless of the quality of the outfits and having a universal ticket would reduce sales cuz you can just hoard on the gachas with better prizes.