The magic effect looks like high tech, that is the first thing that comes to my mind.
I think part of that would be because I've drawn a fake anamorphic lens flare which are only really used by things like star-trek and battlefield 4.
Another thing would be that blue flares are always associated with science fiction / space.
I think I might need to make the magic look more like fire, my issue with that is I'm trying to give the game a super consistent color theme all throughout the interface and stuff.
I'm trying to steer clear of red or gold as it's pretty much what every fantasy/medieval game ever has used, it makes things look samey/generic
I think it is not only that. The shape of the flash looks also too technical/edgy in my perception for magic. May be you can work on that too.
I might add, the sword looks broken/weak/powerless. I would add a weapon which communicates more power/confidence. Since art seems a strong part of yours I would go sure to flesh out enough details in the final cover communicating all the attractive things your game ideally represents.
For example I chose the following pic recently to represent my upcoming Super Metroid Tournament.
It is just one static pic but you can feel it is expressing intensity and dynamics of a battle (not that it matters much in my actual situation), like a charged eagle confidently speeding down towards its prey:
http://www.youtube.com/watch?v=RynVypmFckUFor some brainstorming, you could also think about displaying the opponent aswell since your art skills allows for that freedom of expression. May be showing an ideal fictive snapshot from the heat of a battle. It can also be a stare down of the opponents, depending on what you want to express. I think it can all look "awesome" with enough level of expession.