I feel that I need to make this post now that I've seen a lot of submitted decks: To be honest, the majority of the decks would, if ever incorporated into the game, lessen it's quality compared to the status quo. That may sound harsh, but there's still time to submit great decks.
The biggest problem by far is that most decks feel like ARENA decks, not like AI decks. Where is the difference? Have a look at this current AI3 deck.
Hover over cards for details, click for permalink
4vc 4vc 4vc 4vc 4vd 4vd 4ve 4vk 4vk 4vk 4vo 4vp 4vq 4vq 4vq 50u 50u 50u 50u 52g 52g 52g 52g 52g 52g 52g 52h 52j 52j 52k 52k 52k 52n 52n 52p 52p 52p 52q 52r 52v 52v 52v 8pk
...or this.
Hover over cards for details, click for permalink
4vc 4vc 4vc 4vc 4vc 4vc 4vc 4vd 4vd 4vd 4vf 4vl 4vm 4vm 4vm 4vm 4vo 4vo 5bs 5bs 5bs 5bs 5bs 5bs 5bs 5bt 5bt 5bu 5bu 5bv 5bv 5c0 5c0 5c2 5c4 5c5 5c6 5c7 8pn
Now let's have a look at a deck close to what most people submit.
Hover over cards for details, click for permalink
5rg 5rg 5rg 5rg 5rg 5rg 5rg 5rg 5rg 5rg 5rg 5rg 5rk 5rk 5rk 5rk 5rk 5rk 5ru 5ru 5ru 5ru 5ru 5ru 5v1 5v1 5v1 5v1 5v1 5v1 8ps
Do you see the difference? The AI deck has MANY DIFFERENT cards. It is FUN to play against, because everytime you do, it works DIFFERENTLY. This is one major reason (Yes yes, not the only one. You can also build decks with few different cards that are fun and creative, but that's not the majority.) of why AI decks are fun to play against, and why most submissions so far are BAD. Sorry.
So... please. Take that to heart and build some kickass creative decks instead of arena decks. We are shaping the next years of Elements here probably, so give it your best!
P.S.: It is not forbidden to build duos without a strong synergy.