Honestly, if they have the server resources to spare, I'd much rather they put them into additional housing instances. >_> As far as I'm aware, housing is the other big load in the instance servers besides dungeons - so it's kind of an either/or thing there.
Maybe some kind of extender would work - if you're at keyboard, when it gets to 5 minutes remaining, a pop-up appears with the option to extend your instance another 90 minutes up to a maximum of 2 times (creating a maximum instance length of 270 minutes, or 4hr30).
I just don't think indefinite dungeon instances is something that's practical to ask for. It's got too much room for exploitation (because you can bet it'd take less than a week for someone with beef with FFXIV to try and attack the game by mass-occupying instances in a DDoS-style attack).
Maybe some kind of extender would work - if you're at keyboard, when it gets to 5 minutes remaining, a pop-up appears with the option to extend your instance another 90 minutes up to a maximum of 2 times (creating a maximum instance length of 270 minutes, or 4hr30).
I just don't think indefinite dungeon instances is something that's practical to ask for. It's got too much room for exploitation (because you can bet it'd take less than a week for someone with beef with FFXIV to try and attack the game by mass-occupying instances in a DDoS-style attack).