You have the option to repair before entering, therefore you are not at a disadvantage. If you forget, it's on you. This MMO is not those MMOs you keep referring too, it's a different one. There are games that punish players far worse even than durability on gear. We can always go back to losing experience and even levelling down like in FFXI if you so want other MMO stuff involved.

It's not that bad to run to the retainer to change glamour when you want to do it. Do you really have to change glamour in the middle of a dungeon? Does that really mean an NPC should be added to dungeons to fix your stuff just so people can change their underwear halfway between fights? I know you say you don't like crafting, but all you have to do is turn ins or even leves etc. to level your crafts for it, takes awhile that way, but it works out so you don't really need to do the 'boring' crafts yourself, and then you can repair yourself.

If you forget to repair, and your stuff is broken in a dungeon, just go along with it. If it's something that really punishes you for having some broken gear, then the 30 min should teach you in future to prepare well for such things.