I think FKG has room for improvement, namely stamina regen. It's not level based, so as you level up, it takes times to fill up your stamina bar. It would be best to change the stamina regen, something like the regen is such that every 6 (or a fraction of 24H) hours, your stamina bar is fully charged.

I personally would like to be able to purchase this game and have them do away with the stamina bar altogether.
Although I suppose the slow stamina paces the game so you don't roll special events in an hour flat.

The stamina regen is meant to be slow, much like how it is in aigis. You log on once every 4-6 hours to spend stamina and then log off and do something else. It is a slow game compared to PPS and similar, but it is also meant to be so that you can do other things~~

I personally wouldn't want it to be changed.

Same goes for me, I like how it is. More level = less stamina loss while not loggin in. For myself at lv80+ I need 15h logged out to have it back to full ^^

What would be great as an improvement should be a mail box in the game.

You can always recharge your stamina instantly. Just saying~ XD

You can already gather every two hours to get upwards of 20% of your max stamina. Stamina system is fine.

The cost of some daily/event maps are a little overwhelming, especially for newer players, but it's not a dealbreaker.