It would be cool if we were able to make an in-game journal/notepad that the player could actually write in. And/or maps the player could makes notes and sketches on.

Would something like this be possible?

I second this request. One of the best mods in Morrowind and Oblivion were the journal mods. I'm already playing with live written journals, but it's a whole different experience if you can do it in game.

And yes, this is 100% possible, it just needs someone to do it.