DragonAddict, that is a long list of items covering a diverse set of challenges. Of course I side with making the game system more stable first, but let's just look at more intelligent NPC behavior and animation modeling, as that would cover most of your topics. Let's say we boost Sera for more dynamic and independent behaviors:
- swimming -new model
- scouting where she opens up map areas and might hunt or mine
- shopping and unlocking things automatically and
- new idle behaviors when she is waiting -practice with her bow, pray, meditate, daydream, sleep, etc.
Also let's change Sera's body to be more like an elf. See how that goes across platforms.
- you need to upgrade the processing power of the NPC decision matrix to do more tasks and
- account that she and any others helping her are unavailable
- the dialog and script engines to communicate her tasks and
- the audio files for any new sounds, maybe actress/actor voices and
- the animation models to make the NPC and other behaviors look realistic and
- the artwork to support the new activities
- probably need the writing staff too
This is just one NPC and immediately you run into the question of how many advanced NPC's can a platform support? So you also need a system to determine what a platform can support, several advanced NPC behaviors or none. DAI currently has no method to select which DLC you use and that also needs to change. In any event, you now have the grounds for several months of work, but much of it will support other characters down the road -synergistic development.
Not made for PC? Silly, EA/Bioware have no reason to exclude PC markets and every reason to reach for more. A lot of that MMO feel about the game is the Frostbite development system's network of machines that allow development in a living world. You write the NPC dialog while moving the NPC around and interacting with objects that others are placing in the system. It likely "feels" like an MMO while the staff use it.
Also take a look at the nexus - more mods go up every day and look at the notes and warnings, many modders still see DAI as an alpha product.