Having read your post and while I realize you have some concerns, a lot of your information is wrong and as such I would like to correct some of it as it may be beneficial to you.

"It makes them impossible or painful to complete on low population servers, especially late at night" - This is not true, the duty finder matches you with players from other servers in addition to your own though as a dps I usually expect a 40-60min queue late at night.
"the animations and dialogue are always about your character and not your group" - While this is true for most dungeons, I can think of at least one where your entire group is represented in the cutscenes.
"You can be Level 50 and skip completely beyond the main quest chain" - You could do this, but the endgame content requires that you finish the main storyline, meaning running at least 10 dungeons in order to access the level 50 content.
"Why are you giving players items they can purchase from vendors when in all likelihood, they have more Gil than there is anything worth spending Gil on below L30" This is for people like me who focus on crafting. The first class I got to 50 was goldsmithing when my blm was around 34 and as such I got by on the gear given to me by quests and dungeons.
"topped off with the worst games as a service maintenance schedule" Maintenance is usually advertised a good few days in advance although admittedly there was quite a few emergency ones a few weeks back. You have to remember that maintenance will always effect someone. Being from the UK, its usually us who get hit with the maintenance during prime time in most other games but here it usually occurs when i'm sleeping so for me its a nice change.

Hope some of that helps