Just got the game last night and yes, I know it's early access but there are very simple things that can be done to polish things up. From a new player's perspective here's my list:
* Key bindings : The most unintuitive set of keys ever! :) Esc to menu would be nice, enter/space for select would be nice. But G/Y ?!
* Opening lines/Taunts on win or loss: Have a different opening line for some God-pairings eg. Athena vs Zeus : "I'm not just Your little girl anymore, Dad!" "Leave this to Daddy-Z!" / (You win!..) "Better get home to Hera before She finds out!" / (You lose!..) "Yes Dad.. back to My room.."
* End Boss : I know it's challenging but those 80% combos!? Needed a near perfect game to beat him with Athena.
* Skins are all just recolours? - not much of a skin :-/

* God balances :-/ This will take time - but definately needed to be mentioned
** Moses: wtf? unblockable moves which chain into Ultimates?
** Jesus: wtf? those combos..

I'll leave the God suggestion to the pinned thread,