Since this discussion is going on for a while, I might as well toss my 2 cents in:
I do not really miss unranked at all in Duelyst since I didn’t play unranked at all in comparison to ranked mode. Therefore, I did almost all of my meme-decking and deck-testing in ranked mode, just like how I was doing to ever since the very beginning of my Duelyst career. If I had more free time in real life, I can really push myself beyond silver and enter gold and beyond.
More to the point, I don’t think Duelyst really need to have an unranked mode as badly as the competition like Shadowverse for example. I think this is due to a single difference between them, which is the way to gain the in-game currency to get more card packs. In Duelyst, you always gain points towards completing those daily quests, regardless if you are winning or losing. As a result, I was able to gain new card packs on a regular basis. Those boss battle rewards help out as well with my collection.
Contrast this with Shadowverse. You only gain points towards almost all of the daily quests if you actually win the matches. Sounds nice, but I have reached the point where even my peers run very expensive and powerful meta decks in unranked mode in an effort to complete those daily quests. And this goes on even in the middling ranks of the game. As a result of these powerful meta decks, my win rate dropped like a rock and my progression rate and motivation goes down along with it. Nowadays, I just log into Shadowverse to claim the daily freebies and the free packs they hand out time to time.
From a fun, meme-ly perspective, I understand the appeal of goofing off without consequence in Unranked. However, from a business perceptive, my observations, and from the reasons CPG stated, I do understand why the mode got the axe like it did.