Zewpi
Make them.. way harder.. like.. 2-3x harder. But almost always guarantee at least 1 drop - I wouldn't mind spending 2-3-4 hours in a heroic if i knew i was going to get at least something from it. When you consider that's essentially how long a raid lasts in WoW and you're potentially clearing a whole raid in that time and getting rewards rain down upon you.. it doesn't seem like it's too much to ask for?
Certain dungeons feel unrewarding - that's nothing new, but grinding unrewarding dungeons to get heroic keys then grinding those heroic dungeons which also feel unrewarding is just not that fun. The heroic content should be literally that, heroic, scaled to a minimum of 700+ even for the weakest all the way up to 1k for the harder heroics, but upping the drop rate considerably. It may be just me but i don't feel as though heroics should be content that you grind - but more like you should get a couple keys and get the best group available to have a go at clearing it, it should be very difficult, for well prepared 6 person groups, but with a good yield to compensate that very same well prepared 6 person group.
I did write this originally in my MW feedback to Red, but maybe also couple this change with a reduced drop rate on heroic keys so having a go at them is an OPPORTUNITY rather than a given. Especially if the drop rate inside heroics is increased.