I'm going to give this a try, although it seems very intense in reading the functions; probably far over my brow. I think it would be vry useful to create multiple-option dialogue, and Dragon Quest style menu options. If it cn do custom subscreen functions, so much the better.
I also see high value in title screens with this... Consider also that this would allow the player to enter a name and store that as a constant (e.g., TANGO_SETNAME, TANGO_GETNAME) that is different to that of the .sav file name, and then use this in-game, and as the name is stored as a string of some kind, it can be longer, while still keeping the quest name in the game selection menu.
I expect that once I figure out how the styles work, most of the other functions should be easier. I expect that your goal here is to streamline all of the functions as well as resolve any game-breaking bugs?
In a final version, I would love to see mass functions such as TANGO_DIALOGUEBOX and TANGO_CONTEXTMENU, for making a dialogue box that is associated with specific strings, and follows an if / while chain, and a context menu for making a simple DQ Examine, Take, Search, Inventory, Spell, etc. type of menu system, particularly if it is easy to establish the functions of these.