1. Decide if a game is dark and serious or light hearted parody. DOS sometimes flits between the two with e.g. banter between the protagonists not always matching the mood of the narrative. Either is good - mixing sometimes jars IMO. This is not to say a "serious" narrative can't have comic interludes/character cameos (see Shakespeare for example), just that they need to be placed carefully and partitioned so as not to break the immersion and mood in the main narrative.). Another way to put this is that an RPG can go for suspension of disbelief or it can go for tongue-in-cheek but it can't really go for both.

2. Character customization options. Bulging biceps and mega-boobs are not my thing, nor do I like ridiculous and impractical attire. I'm not criticizing DOS for this because on a limited budget doing proper avatar construction and detailed in-game attire modelling would have meant sacrificing game content and i would rather have content than looks, but for the next game this should be affordable given DOS success. Nothing wrong with massive biceps and mega-boobs for those who like that sort of thing, but the option to create your characters in the image you imagine would be really nice.

3. Major inventory management overhaul. There are so many ways to make it better I'm not going to grind through them all. If you're going to have masses of "stuff" to deal with, and lot's of players like that I know, you gotta have the tools to manage it easily and effectively. it's a big quality of life issue in RPGs.

4. Major crafting overhaul. Apart from some basics like making health potions and weapons it is almost impossible to craft stuff without alt-tabbing to a crafting guide or risk losing your sanity. Expecting you to write up your own personal crafting guide manually is not IMO an option in a modern game. If you are going to encourage experimentation you need to support that by recording successful recipes for future use and also provide a system to eliminate failed combinations somehow. Skyrim did this for alchemy for example. Make it deep and complex as you like, sure, but give the poor player the tools to capitalise on their efforts without it feeling like going to work or a double physics class on a Monday morning.

5. Highlight new dialog options (in bold for example).

6. Put the main game log (the equivalent of "A source Hunter's Journey") in a separate tab and open it pre-scrolled to latest entry to encourage it's more frequent use (by bothdesigner and player) and .