I am new to Doomlord, but I have played similar games for quite a while. Let me start by saying so far, I enjoy Doomlord the most. Aside from the game mechanics, having the developers read and post on the forums is a huge plus. It's the reason I gave this game a try in the first place.
That said, I do have some suggestions. Apologies in advance for what is likely to be a long post.
To me, the key to a good game is having an active, engaged community of players. The quiz feature is an excellent example of this. Users submit their questions and get to see them used in the game. That means they added something to the game, and they become more emotionally engaged. I saw another suggestion for more variety in monsters, battle texts, etc. This same mechanism could be used to satisfy that user's desire. It would obviously involve a need for more moderation to review the submitted pictures and text, but as long as you have users who are willing to be the moderators (an even higher level of engagement), the same review process should work.
So far, I have seen relatively little interaction between players. There are these forums, but they seem to mostly stay pretty on topic. Nobody is just chatting with each other. Once I join a clan, perhaps I'll see some of that on the clan forum, depending on the other members of the clan. But that kind of socializing really does increase the engagement level of the players. Programming online communities for big corporations is what I do for a living, and the studies I've seen really do support this. Once people start thinking of the other players in the game as their friends and going to the game just to hang out and chat, they are more likely to be willing to spend money on the game (which is the reason for the existence of the game, after all). And even if some people stay non-premium, the fact that they are active and engaged makes
other players more likely to pay. The most effective way to foster this sort of community is an in-game, real-time chat, but the forums could be leveraged better than they currently are. You link to the forums on the hunt page, but there would be a lot more activity if you displayed the most recent few posts there in addition. Once you reach a critical mass of activity, these things become self sustaining, but people need a little guidance to find these things.
Finally, a truly radical (i.e. nobody but me will like it) idea. Let me start with the story of my experience in other games. As the game matures, you lose players. That's just the nature of things. Real life gets in the way. So you need new players to replace them. But nobody likes to feel like they are so far behind that they can never catch up to the leaders, so most new players just quit immediately. Then you open up a new world, and a bunch of people jump ship from the old world to the new, where they can have a chance to be the leaders. This leaves the old world a hollow shell of itself, without the critical mass to maintain the community. It's less fun, so more people leave, and it goes into a death spiral. Now, the radical idea: set a specific expiration date for the world. After that date, it's a complete reset, and everyone starts over from the beginning again. So why even try if you know it's all going to disappear in 6 months or whatever? You give out trophies, and each player gets a trophy case page. You can get as creative as you want want with the trophies - highest level, most damage dealt, highest level pet, most quizzes answered successfully, most quiz questions approved, most quests completed, etc. Some trophies could be popularity trophies, determined by user votes - best quiz question, best user-submitted monster, best avatar, best forum poster. People will still try for the bragging rights, and you will avoid the death spiral I keep seeing. And as a side benefit, reset would provide an opportunity to put in place any tweaks you wanted. For example, if you thought that the emerald horde's ability to buy spells a level lower was too powerful, right now you're stuck. You couldn't change that without upsetting a lot of people, since they chose their horde with that ability in mind. But at a reset, you'd be free to replace that ability with something else.
That's (more than) enough for one post.