Firstly would be certain philosphical issues. In this game you will spend alot of time talking and solving puzzles, there is no correct way but a running score will be kept of what path you take. The maker of a module can use this information to their wish.
If you are not into reading and then showing comprehension of such then this would not be such a game for you, there will be a fair bit of reading involved. it has many academic leanings. For example the magic system will actually be a formal system, have its own language (the use of F#) which affect how the spells unfold. The system will be simple with a set of a few rich rules but the most complicated systems are like that.
But that is far in the future. I wish to begin exploring philosophy, where it is possible to argue certain planes into existance and then visit them but before that there are a few basic gameplay elements I wish to lay down.
In this game you can start out as powerfully as you wish, an experienced archmage or a simple apprentice it does not matter, the fighting element is not the only way to progress in power. And even then, you can gain power without lifting a hand to allow the defeat of the more powerful creatures if such a need ever arises.
-You choose your name and background. There are a few pieces you can put together, i.e. the idea is that you can make your history, a lord or not, orphan or with live parents, old or young all these affect gameplay since the module maker can account for these. Hence your race is picked implicitly. But nothing else is chosen.
-The concept of unlocking powers is key. For example when you are killed you become a ghost. There are several ways to come back to life. Find a priest, convince them to heal you. Force yourself back to life - this will be handled via solving a puzzle, if you read a certain book then you will know how to enter a certain 'shadow plane' and do a quest that lets you auto live when you die. You must convince (using your own intelligence) a certain being to keep your mortality safe to you wish it back (what penalties this incurs can further be reduced as your character gains in power) and finally enter the shadow plane and fine a doorway back to yourself. This will be in the first module. But accessible in any module forward.
-Apart the first module, you can start from any module you wish.
-The game will be part based on live skills and character skills. For example, your past determines your strength but your actions determine the ingame intelligence and wisdom.
-There is no health at first but in the first module there are several way to make your self less vulnerable. You can learn how to alter the probabilities of a certain event occuring in your precense, specifically getting hurt. You can create magical shields that are run down, they drain from your mental reserve. Which when too low causes you to hurt and then die. Alter the chaos and order balance of the weapon swinging you, psychically affect the weilder. All these are unlocked.
I tire of typing.