Having the ability to create our own codexes is unlikely because of the new style of recording codexes. Though I would very much like to be able to make records/notes on the computers/monitors in this game would be rather interesting. Due to the fact that these computers/monitors have no current use in game other than aesthetics, which I don't tend to care about to much (sorry to all you builders). I would like to know from others if they think this is possible/other improvements. There is probably a mod on this but I personally have never been able to make a mod work.
Could be simple to implement. Make a recipe for a tablet or digital book of sorts, using a bunch of electronics. And allow the player to write/modify the text. Doubt they'd make every computer have access to such a thing, but perhaps a computer that is designed for logging and notes. (Perfect way for a Fallout Terminal reference here guys).
I also forgot to mention that the fact they have a map display ALREADY in the game kind of tics me off. Why put it in game when all it does is display a small screen showing a typical USCM bunker, impractical for builders and me, The map should have some sort of guide or st least a sort of frame like drawing animation so we can draw our house into the map.