Look; I get that "what looks good" is going to vary from person to person, but the Death Knight's Mythic Tier 21 set (read: the Blue one) looks way less interesting than the other three, particularly the Normal and Heroic versions:
http://www.mmo-champion.com/content/...-21-Armor-Sets
Really, this speaks to kind of an ongoing problem with Death Knight armor, I think. It's not that Blizzard doesn't know how to make some cool-looking armor (although the DK's T20 was pretty weak), but that they rely *way* to heavily on using a single color to carry an entire set of gear. I mean, look at the Heroic version:
http://media.mmo-champion.com/images...eroicRough.jpg
You've got a really visually-interesting suite of colors at play. The blackened plate with tarnished gold accents, punctuated with blood-red highlights. There's a lot going on, but the colors all play off of one another, much as the Paladins' favorite set, the Judgement Armor, had.
Now, compare that to the Mythic set:
http://media.mmo-champion.com/images...ythicRough.jpg
That set is BORING AS SHIT to look at. The only splash of color are the brown leather straps, which don't even compliment blue. Furthermore, they're matching the color Blue with OTHER SHADES OF BLUE. Looking at this set makes me want to fall asleep at my keyboard.
Hell, even the LFR variant at least plays up some brass/golden accents!
Personally, I would change the armor to use the bright Purple-and-Gold coloring of the Nerubians:
https://vignette3.wikia.nocookie.net.../Cryptlord.jpg
Now *THOSE* colors would look great with Blue highlights (or hell, even Green, even though it's been overplayed this expansion). Or maybe even incorporate some Burgundy accents into the existing design.
Either way, the existing Mythic set just looks painfully drab in comparison to its Normal and Heroic counterparts. So, hopefully they'll do something to spice the armor up a bit more.
And hey; while you're at it, how about some asymmetrical shoulders again? Those are always a hit.