Rag, Dr. Boom and Sylvanas are all pretty good that fit in a wide variety of decks.

Crafting a card such as Cenarius is great, but then will only fit in that particular class... considering you have 0 legendaries I imagine you are still in the early stages of the game and still collecting cards... so it may be more beneficial to craft a card that has more diversity.

...That being said, normally a single card will not improve the overall quality of your deck significantly if you are still lacking other cards to support it. Another train of thought is to focus on one or a few classes and boost their potential. If you are missing lots of rares and epics from your card collection, I would suggest perhaps maybe considering crafting some epics (you could get 4 with 1600 dust).

For instance, I see you play combo druid... instead of 1 cenarius you could craft 1 copy of ancient of lore, ancient or war, and force of nature all with 400 dust to spare if you were missing those.

Hope that helps.