Hero's Hall sounds great as well as the power-up shop. Im also an avid gamer and feel the site if more of a to-do list then a game but as long as I get points I'm happy. To expand on Karl's idea you could have a little character icon where the current stats relate to traditional game stats like health, strength, charisma, agility, dexterity, ect. And then as one levels up they can get new gear to dress their characters. And even further the heroes hall could be a little environment where your character could walk around and talk with others. But thats getting really fancy... A simple update to the website would be great also a game style character sheet would be fun. If you look up RPG character sheet you'll find tons that you can base one off of.
I would also like a more gratifying reward for gaining a level. I know others have mentioned wanting to be able to personalize their secret labs and such so I was thinking that that would be an excellent reward. Also, many sites use badges to encourage people to contribute and do things, they may be another option for rewards.
I actually came on here for anxiety problems and found that none of the pre-made power-packs were things I needed to work on. for example I ride horses so I exercise everyday and I don't eat very much. Also I had already tried many of the suggestions in the anxiety power packs. Now I am currently creating my own set of power-ups and quests tailored to my personal life and I have been able to improve bad habits.
I would also like to be able to sort my power ups, bad guys, and quests. Some are one a week basis while others I would like to do ASAP. If i could organize them in order of how i want to get them done it would be extremely helpful.