A bit similar to my post in the other topic, but (long post on factions below):
The thing that I would like to see the most in TES VI would be much better, deeper factions, as well as a larger quantity as well. I really could do without factions primarily being based on some 4 hour cinematic experience.
Factions should represent different perspectives on political, cultural, and philosophical issues, and fit in with roleplay avenues pertaining to the regional experience. Furthermore, not all factions should be some shade of gray. I think it's perfectly fine to have some highly benevolent factions, many grayer factions, and some malevolent factions. Variety is key here. Furthermore, joining a particular faction should change the way certain groups of people perceive and behave around you in meaningful ways, to the point of some groups being hostile, others not wanting to associate with you, and others pledging their support to you or complimenting you everytime they see you, or maybe radiant quests popping up from these things.
Going into the field of consequences, many actions in a particular faction should have a host of effects on the world or area that faction pertains to. If I join the Crowns, I shouls have the option to achieve power through diplomacy, through espionage, or through more overtly destructive endeavors. Each of these choices should result in a different political landscape and different effects on the environment.
Furthermore, if the player-backed Crowns aspired to power, there could be numerous decisions to be made. Things like deciding whether or not Orsinium should be allowed to exist or should be eradicated, whether Hammerfell should remain independent, or whether maybe cutting some deal with the Thalmor might be in the region's best interest. Each choice should have consequences, and often times choices should snowball into bigger consequences. If you happen to incite war with the Forebears and Lhotunics, while declaring Orsinium to have no right to exist, perhaps then Orsinium, Lhotunics, and Forebears would join in alliance, or any number of mixed consequences based on some radiant algorithm.
I'd also love for espionage quests to exist, and for us at crtain stages to have the option to betray certain factions, or maybe even catch espionage in the act if we happen to look hard enough. Perhaps even an Awareness attribute could give some unique ability to notice these things. Political factions should be full of radiant unpredictability, with a lot of different decisions and methods for enacting these decisions. Disguises should also be a thing, where one can infiltrate a faction location if they're careful enough.
Not every faction would need to be so clearly political, but in a Hammerfell game, I would love to have most factions be some degree of Yokudan traditionalist, non-Yokudan modernist, or neutral/middle of the road.
Additionally, for ideal factions, I'd like to see the main quest line held back until one gets fairly high in rank. Until then, one would primarily be involved in jobs, favors, and quests (non-story) for the factions. Additionally, I'd like for skill and attribute levels in archetypal factions to play a role in progression. Not every faction should have requirements but I think it makes sense for archetypal ones to have them.
Lastly, I'd like more emphasis on roleplay in the factions, which should also contribute to progression in the hierarchy of the guild and also provide ways for enhancing gameplay.
A magic guild should have numerous roleplay devices, like topical lectures/classes on lore related to magic, exploration or excavation of magical ruins, or a practice hall where one can train specific spells and provide a spell morphing system which could function like spell creation.
In this system, one could gain experience from using a particular spell, such as unrelenting force, which they could use to edit spell details. The spell details/attributes could be things like spell duration, impact, magicka cost, damage, area of effect, etc. Additionally, spells could level up, providing an additional effect morph, where you can do things like making a spell more silent and weaker or louder, much more chaotic and hard to control, but more powerful, or even add an entirely new effect to it, such as disintegrating enemies who are below a certain health amount.
This same principle could apply to stealth/acrobatc abilities in a stealth faction, sailing stuff in a pirate faction, weapon-specific techniques in a warrior faction, etc.
One should also have the option to not be the guild leader if they wish to. And being a guild leader should have some sort of new stage of gameplay or management.
But yeah, this is the kind of thing I'd enjoy, to whatever extent it can be done. We also need Morrowind or greater quantity of factions, imo. I think these kinds of things should have greater precedence than cinematic storylines.