It would be cool if GW2 dungeons would allow 5 or more up to whatever the hardware would support to run. If 23 people entered a dungeon instance then the dungeon would scale for 23 people. If 5 people entered then the dungeon would scale in difficulty for five.
Several times we had to split into multiple group runs on the dungeons and 5 is sometimes just too small.
Maybe we could look forward to this in an expansion.