As a programmer by trade, there are some games that "wow" me, in that I wonder how things work in the background, and how they went about doing what they do.
I've always wondered how the time-rewinding works in things like Fatal Rewind, Blinx, PoP, and Braid, for instance. Conceptually, I have the basic idea, but that's a massive amount of what we call "state" that needs to be stored. I assume that can be reduced by limiting sprite movements to certain cyclical paths at a set timing loop and keeping track of the player's pathing, but I'm not sure. Sorry, rambling off topic...
Skyrim was another one. I can't imagine how they keep track of every single object and actor in the world. The non-random actors are probably similar to the sprites in the other games above, in that they always travel a set path (I haven't tested this, but I probably should). I.E, that Whiterun guard is always walking past Warmaiden's at 9:17PM every night sort of thing.
But keeping track of the location of every single stupid "flavor item" like bowls, tankards, and chamber pots? (Seriously... do I need to be able to pick up wooden ladles when I'm trying to grab the snowberries?). Or the items that constantly respawn in the dungeons? Every one you drop while outside becomes another object for the game to track.
The hundreds of iron daggers and leather bracers created by smithing grinders? If you lug them to a merchant and sell them, they'll get garbage collected during the next refresh. But if you're already lugging around tens of thousands of gold and can't be arsed to find a merchant who hasn't already given you his entire liquid holdings, and chuck them on the ground? More things for the engine to track. In my game, there have been a dozen bowls, cups, and useless books sitting outside Breezehome for 25 play-hours now.
So how does the garbage collection work? Apparently, there is some, since when you leave something behind that you want to pick up later, it's usually gone when you get there (or maybe that's just my bad luck?).
I think Beth has too much of a hardon for "persistence." Sure, it's a cool concept, but when you combine it with the amount of freedom they give you in the name of "realism," I can't imagine a system that would scale without taking up massive amounts of memory to hold the state.
The freedom is good, mostly, don't get me wrong (although the new system still doesn't protect you from the Oblivion problem of 'leveling yourself into a corner'), but we can do without some of the 'realism.' I mean, we're running around killing dragons, casting magical fireballs, and shouting at people with enough force to drive them off of a cliff. I think we can live with our "Moldy Tankard of Tarak-Nor" disappearing after we've left it on a rock in the distant corner of Skyrim for a few days. "True-to-life" isn't the message of the day here...
Hell, if we really wanted "realism," the best seller would be a game where you get up in the morning, go to work at a job you hate, sit in rush-hour traffic for two hours on your way home, then drink yourself to sleep while having sexual fantasies about women you will never ever have. Yeah, I smell a GOTY there <_<.
(Holy crap... at least I don't think I have to worry about a low-content post warning!)