I recently started this character : http://www.elderstats.com/character/3827/ on master difficulty.I have found that playing on a higher difficulty has made the game alot more fun.When I played on adept I did not pick certain perks,did not smith weapons,and did not do other certain things to keep it challenging and balanced.On master difficulty...perks,skills,enchantments,potions,weapons,armor...everything is alot more useful and necessary to survive.Dragons are deadly on master.It kinda feels like that first day I played...Battles feel epic.

For example...my character left Old Horalden headed for Karthspire.An ancient dragon and a blood dragon appeared,my character used the Bend Will shout on the ancient dragon,jumped on it and proceeded to attack the blood dragon,aswell as the Foresworn at Karthspire camp...it took just over 45mins to kill everything in the area.The whole time my character was riding the ancient dragon.Awesome battle,lots of fun.
(I died once during this battle,after about a half hour of flying around on the blood dragon vs the ancient dragon...in mid air the ancient dragon animation looked as though it came at my dragon with its talons and knocked me off the dragon and I fell to my death...one of those "oh wow" moments)

So if you feel like the game is stale...I recommend switching to a higher difficulty.

I had a pretty epic battle with the mercenaries at Goldenglow + a blood dragon the other day. Playing DiD on legendary with leather armor(roughly 250 AC with perks @ level 21) made this fight ridiculously intense.

I think the higher difficulties make things a lot more interesting(especially at low levels). Not using potions also makes combat more enjoyable to me. Instantly healing yourself to full while pausing combat is just going to get boring....

Master is funner all around, unless you're playing a mage.

I started a Legendary playthrough about a week ago and I know what you mean, its sooo much cooler. Another thing Im doing is saving dragons until they spawn at least Ancient level, so that dragons never seem too weak. Ive encountered a weird bug with it though. Enemies will randomly seem weaker than they are supposed to be. Then I check the difficulty, it says Legendary, then it saves when I leave the menu and the enemies(even the same one I was fighting when I opened the menu) were strong again. annoying.

But anyway, I agree the game mechanics new to the series with this game, like smithing really strong armor and weapons, and perks, work way better on a harder difficulty.