That's not always a magic fix as people seem to treat it. "Make it optional/a slider/etc" comes up all the time, but it's not that easy. Difficulty needs to reflect game balance; a very simple, common example is a game setting the difficulty of a boss according to the level and amount of supplies the character is expected to have after the dungeon. A temple at the top of Horrible Pain Mountain is hard to get to, and that's the point. What if there's a powerful artifact there? Should the player be able to turn off environmental dangers, skip up the hill, and claim it five minutes after starting the game? What about the supply items, stat penalties, and balancing that need to exist solely for these features? Too many optional things and you get to the point that you're asking them to make two different games, which is a much bigger threat to the end product than this strange disk space obsession that's also floating around.
What you're forgetting is that the standard game is without any of the optional effects. When we suggest optional aspects such as hunger, thirst, etc, they are to make the game harder. Without them, the game would be of a normal difficulty.
For example, you may feel Morrowind/Oblivion are of a standard difficulty without any of the realism mods, but with the eating, sleeping, drinking, or whatever mods, it will make the game harder. If you don't want the game to be harder, don't use these mods. It's the same for optional settings.
I also doubt the difficulty slider is going, most of us love the ability to make the game harder when needed. I'm pretty sure there's a majority.
EDIT:
While we're on the topic of race asthetics, I'd like each race to be more defined. I would like to have Orcs to be so muscley that they're kinda disformed, similar to WoW (but not as exaggerated), and man races to look a lot more significanlty different to the other man races. Nords should be big and strong, Imperials should be the medium, and Bretons should be weaker. Beast races should also get thier Morrowind forms back. The helm/boot problems require the tiniest fix. I mean, if we can do it in the CS, surely Bethesda's massive team could figure something out.
Of course, with the aforementioned system, some NPC's could look different dependant on what they do. A Warrior Breton could be muscular, a Nord mage could be skinny/fat.
I think the "lazy" classes, that don't do as much physical exertion as warriors, such as mages, should be either fat, or skinny, unless they have some strength or agility. (Think battlemages, nightblades, etc)
Also, most nobles should be fat. Some should be the knightly type,, and keep in top shape, but most should be overweight, being the lazy "everyone works for me" types.