I have several simple wishes.
Firstly, I have noticed that Xie's hunger mod is wonderful.
It changes the way the player plays. I love the Nazi Zombie styles Nightmare mod, for which I do not remember the name of the creator. Anyway, that mod works extremely well with the hunger and farming mods. (Surprisingly to me at least.) I noticed that I could hole up in a stone wall surrounded area at least with line of sight mob targetting off. This would force me to create food with the farming mod and exit to gather resources. This is a unique and amazing experience, changing Minecraft into a largely survival based game.
However, during this I noticed a lack of any ability to change speed beyond crouching and walking, and also most mobs move at the same speed except for jumping. I would love to see a spring function, for players and appropriate mobs like wolves. The real star of this rant is SLEEP. I believe that a need for sleep could add a great deal to the immersion aspect of Minecraft. It is established by the hunger mod by Xie that a timer can be used to trigger a change in player status, and the Succubus mod (Creator name lost) establishes that camera interference can be implemented to great effect. I would like to see a simple sleep mod in which the player would have a timer that would cause the player to perform better or worse based on the amount/quality of sleep he/she has had.
This would require elaboration. As you go without sleep, your vision could become blurry. This would be hard to add I think. Alternately, your vision could become increasingly shaky, this CAN be done as shown in the Succubus mod. If you go FAR too long without sleep, your movements could become sluggish or unresponsive and the camera could start blinking out to suggest extreme fatigue. Maybe attacks could be weakened, but these are all just ideas.
A bed would need to be created, and I think several could be made with common sense prevailing. For example:
  
Straw bed, just straw on the floor. Poor sleep.
  
Wooden bed with pillow, better sleep, needs mattress.
Much better wood bed with mattress and pillow.
The pillow could be made by placing and a feather together, or again just wool.
I feel like this mod could tie into the sprint function, aiding or hurting the player performance and maybe even being tied into hunger. This would require a seperate item generically called "Condition" which would improve if well fed and rested and possibly uninjured.
Note that I am going far beyond reason at the moment, this is because I have seen some excellent modders here and expect all of these to be possible at least.
Also, minor complaint, it seems like many .class files for mods use very common names, why can't they use rarer names like rather than girl_cry.wav they could use girl_cry1463256.class!
I could not mix two very good mods for humans because of an event like that where both files kept overwriting the other.
-Stolas the owl
Request, misc. I want to use the Animal Crossing Mod, but it does not have the textures for the multi-colored wool or the bones or other materials that have been added in the relatively recent update. I want this to change. How?
Funny you should mention this... my buddy and I are currently working on a mod like this... I may or may not include your ideas... I was just going to make it so that you use wool, half blocks, fences and a pillow block to make a bed... we shall see.