You and the op are in the minority. No one, and I mean almost No One wants a slow, longer dungeon. They are trying to level as fast as possible. People Leave over dungeons taking too long. You would literally be losing people left and right trying to get a slow dungeon accomplished. You would pretty much be stuck with people who do not want the deserter debuff in those. Even then,, they would do anything to speed it up.
OP: No. When I am leveling, I get enough headaches once I reach the death knight levels. A ton of people rolling dks and being horrid. Even without heirlooms, the leveling dungeons are a Joke. The only time they might be hard is if you chain pull too much.
Look, the fact is, people are leveling to get to the engaging and fun content. Leveling, the dungeons during leveling, its not the best or most fun part of wow. You want engaging and fun? Get to max. Leveling is nothing more then a stepping stone to ensure you somewhat understand basic mechanics for your class at max.