horse combat crossbows the need to eat and sleep, also toggle-able multiplayer (free) These are all important... though I suspect TES will be one of the bastions of single-player for a long time... TES just don't have the setup/experience to make multi-player work. But for me, the most important thing would be a cleaned up and improved game engine. I'm not talking about the graphics or physics engines, but the game mechanics stuff. After doing battle with reverse engineering Oblivion fatigue settings for a mod, I've come to the conclusion that Bethesda produced a fairly messy engine that they failed to even tweak well... huge chunks of functionality were just turned off by setting things to 0. Whole chunks of game potential were just turned off... for example burden and fatigue attacks/restores are useless because encumbrance and fatigue have nearly zero impact. The Oblivion game engine is both overly complicated, and under featured. Things like Athletic fatigue perks that kick in at discrete "Expert" levels add complexity for little gain. Arbitary thresholds and limits are balls... continuous functions are the answer. Also, many game mechanics benefit from non-linear functions... x^2 is your friend. Most game mechanics can be reduced to a formula to produce a result from a combination of a level of skill vs a degree of difficulty. A simple generic game engine really only needs one non-linear function with tweakable constants to model just about everything... inventing special formulas for everything just means you invent complicated new limitations and bugs.
