The masterfully crafted just-right roguelike. High emphasis on performance and readable graphics, and keyboard manipulation rather than mouse. But mouse interaction must also be well integrated for newer players to learn the ropes. Traditional DnD-esque setting, because it is palatable to everyone and very cherished by many. Time-based, not only in unoffical ladders but in mechanics. Play fast to win more, quick gambles and intuituve descisions about talent progression and gear choice. For example, perhaps a potion of rage lasts for two minutes of real time, though the game is turn based. Quests should be similar, fast completion meaning higher rewards. Difficulty should be such that a player "taking his time" would never win the game. Perhaps the world is about to end in 60 minutes, and you must become strong enough to finish the villain in his lair before this timer reaches its end. But losing is naturally not some terrible state of game that you should be ashamed of. Just like in chess, you just try another game, and if you got close to winning, then you certainly had great success in your game session.

The base game should actually be quite limited in scope, but if the idea takes off, additional levels and challenges (rather than gear and talents) will be added. Eventually a game like this should grown in depth only, adding nothing but intresting generators and randomized encounters, and enemies. Because otherwise you end up inflating good gear and talent progression, and there is only so many ways you can honestly make a +1 Weapon before it just becomes another +1 Weapon, but its green.