25-30 min should be what they are aiming for. Cut trash and cut bosses if the dungeon goes above that.
I'd love to see some vanilla dungeons get some love with a M+ version. The cata dungeon was ok, not great, still more fun than playing last expansions dungeons.
Since when do we called 5 boss dungeons super long?
Why don't they get it? No one wants to be in a single dungeon for anywhere nearing a half hour. That's 4 hours (8 keys × 30 min) for a single toon before either travel time or time in LFG and is already quite the time commitment. If you raid on top of that say mythic then your mandatory time is around 16 hours for a single character (and most guilds require at least an alt as well and farming time for consumables). WoW shouldn't be approaching the time a part time job would take up just to enjoy
SL dungeons >>>>>> DF dungeons. If you want to see some real crying, then wait until they bring back Nokhud Offensive in Season 3 of Midnight lol.