1. Nothing that obviously won't be in the game because of ESRB issues (IE, no nudity, killing children, etc.)
2. Let's stick to core gameplay, everyone knows we want as much territory, as many NPCs and pieces of equipment as possible.
3. Not everyone was giddy about Oblivion (myself included) but this isn't really the thread to talk about that.
So this is my idea:
People were complaining about Bethesda's skill system being really general. Blade makes you really good at two handed swords as well as daggers, Blunt makes you good at AXES (what?). Rather than adding a bunch of skills that are really specific and bloat the character customization, which Bethesda clearly doesn't want to do, you could have the normal numeral like Oblivion as well as a bar. For blunt the bar would look like this:
Blunt: 56 ///-/// Hammers/staves |_______v________| Axes
If you use predominantly axes for a few hours of gameplay the marker would get closer to Axe, and you'd get a bonus to axe damage as well as a penalty for hammers. So lets say you start out by mostly using hammers, and max out hammers. Then you get a great axe. So you use the axe for a few hours of combat and you end up becoming specialized in axes instead. This could also work for swords/daggers, AOE/single target destruction spells, block with shields/weapons, potion/poison in alchemy, etc. This has the advantage of allowing specialization as well as being easily understood.