Besides missions, there could be a random event that randomly pops up to random players that give/take gold, decrease/increase stats, etc.

Or a gift calendar that gives things like say 100 g or 25 scales.

Many games now do this. It would raise actibity on the site, since you would want to log in to claim your free gift, then see something lese and go there, etc. etc.

Or perks for players who have been on daily for say, 100 days, and they get a special item/pet/currency value.

There will be the advent calendar (I heard there is one). :) Don't forget December is coming around the corner...I know it's still 9 days before it.

But, I'm not sure for the rest...I like how it is. It makes the site unique...And different.