More weapons and/or different types of weapons.
E.G. Magic weapons (There would be a separate training mini-game for magic damage). 2 handed weapons that sacrifice your shield for extra damage. Double weapons like daggers that can hit several times (If there's an ability like the multiple hit abilities, it would multiply the hits).
Definitely a pet system with different kinds of pets, some pets attack by themselves, others could heal you, maybe one that could sacrifice itself to revive you if you die.
More idle type stuff like the bank, I know a lot of people wouldn't like that, but personally, I enjoy idle games.
More stats with their own mini-games E.G. Magic, defense (I know health pretty much equals defense, and there's the shields... so that wouldn't really be necessary), magic defense, a double hit chance stat (if it exceeds 100%, then it goes on to triple hits, quadruple, etc. there could be some cap and/or logarithmic function that slows down the % increase per stat up).
If there is a crafting system implemented, create some sort of a shop that you can buy/sell materials and weapons.
More types of armor (including pet armor, if there are pets) such as helmets, chaps, boots, gauntlets/gloves, amulets etc.
More in-battle actions and passive talents.
Classes (each class would have different talents and abilities), E.G adventurer (all around good, can do magic), wizard (low health, low phys dmg, lots of magic damage), knight (tank, can't use magic but does have his own abilities, he has a debuff talent that at first has a higher chance of NOT hitting for a turn, which you can upgrade to lower the chance).
I know that was a lot and would be very difficult to program, it would probably be too big for a browser game also, but I know you guys can do it!
I hope someone actually reads this
