Fable really developed along this route, and if you've played all three like I have, I would welcome your insight. I personally always found the simish stuff in Fable to be engaging and as long as it remains disentangled from the main activities of the game, it was great to be able to work and buy property. The biggest problem with Fable is the one I find Skyrim developing toward and that is it is so incredibly simple. You buy a few shops with some meager start up money and then you just keep buying more with the interest you earn from those shops and so on. Pretty soon you own the whole world. I'm not saying I see them doing something like that in Skyrim, but if they do add in property ownership or some kind of greater economic system outside of the usual kill, loot, and sell mechanic, I hope they do something interesting with it.
Long story short, I think adding more sim-like elements to Skyrim wouldn't have killed it, and given their current DLC plans, it seems to be well in line with what their consumers want (or what they think we want). I think building this stuff into the game from the ground up would be a fantastic idea moving forward, but I would just politely request that you keep it separate from the whole saving the world/empire/whatever schtick and also actually invest some time in whatever further elements you decide to add. Marrying an NPC who has the personality of a broomstick was not a lot of fun, investing time in other systems with similar rewards is mind numbing to think about.