Wind. Wind effects. Rain effects (water running into rivers). Plants picked disappear and gradually grow back. Plants die without sunlight or water.
Agree and add:
If the engine can handle it (and I hope it will, after they've upgraded it), wouldn't it be cool if there were a lot more plants? In oblivion the closest thing to flowerbeds were areas of grass with 1 flower for every square meter. Not every plant would be entirely grown at once, and if you harvest a bed, it would take time before it sprung up again (as you said).
Alchemy would have to be altered along with this though, as you'd have too many plants to work with the current system. Maybe they could make it so that you'd need more than one of an ingredient to make some potions. Maybe you'd have to refine them first or something - then you'd have to collect a lot.
One thing that may need a little improvement.
If they want to put in "humor" they should maybe think about it a bit more. I just played through Shivering Isles and I honestly gotta say, I wasn't really "impressed" by Sheogorath. Didn't really find him funny because his lines mainly consisted of "Barely coherent babble, nonsensical babble, "I'LL RIP YOUR GUTS OUT", barely coherent babble, nonsensical babble, "I'LL RIP YOUR EYES OUT"..." and so on. And if they tried to make him seem psycho, that kinda failed too because he never really seemed threatening.
All in all he was a nice change but seemed too much just weird and random, I know he's the "mad god" but still it felt like he was just haphazardly puzzled together.
However I have to admit, giving NPCs emotions and personality is a VERY hard task, still for this kind of game it's one very worth wile pursuing. It's not really the bombastic visuals, a ear ripping soundtrack and "evil demons from hell" that make those games great, it's the little details. With the big stuff they can be "good", if they actually focus on the little stuff too they can actually become "GREAT".
NPC personality is CRUCIALLY important for immersion. It's hard, but it's worth it. If it was up to me, every NPC would have a backstory and a story that the PC could witness as the game progresses.
Only thing is... I hope they have tons of NPCs in the next game -- not cities with ten people in them, but hundreds! Thousands even!.... but then giving everyone a backstory would tax their resources too much.
I'm not sure which game I'd choose -- one with tons of NPCs, or one with few, well-developed ones... I hope TES V is a good compromise.
EDIT: And I actually liked Sheo a lot -- I think he fit his realm quite well (it's a part of him, after all). He should be random - he should be unpredictable. And nonsense is an entire style of its own. And I have an idea of my own (that's probably someone else's too, but I came up with it - if not first - then at least on my own): Make it so that you can try on clothes before you buy them! It's not important for a game where all that's important is the stats of your armor - but this is a freaking RPG series! People care what their character looks like! This'll be especially important if they're gonna have lots and lots and lots of outfits - which I'd love love love.
And add more individual pieces of clothing -- and individual 'slots' for clothing. Would be cool if you could have a shirt on underneath your armor.