I'm not sure if this was a consideration for you, but you don't have to get pigeonholed by the *D&D stat system.
Check this out:
-Strength/Arms (Affects melee combat, your maximum weight, perhaps maximum bulk if you choose to keep track of an item's bulkiness, and health).
-Dexterity/Hands (Restrict this to be "nimbleness of the hands", so it would affect accuracy of ALL weapons, and skills that require good hands).
-Agility/Feet (This will be speed/reflexes)
-Health/Body (Affecting resilience to poison, diseases, the ubiquitous "hit points" construct

, etc)
-Charisma/Face (Affecting interactions with NPC's, persuasiveness, cost of goods with merchants)
-Perception/Senses (your definition of perception)
-Mind (your definition of mind)
-Essence/Beyond/The Other/catchy name (a good way to introduce the mystery of "magic" into the MUD, present it as something that isn't well known or understood)
I used the convential definitions at first, but I think it would be nifty to find a unique way of representing the stats. In this case, I used body parts. You could use organs, or Indian chakras, or something else unique to add some character and set your MUD apart from the *D&D clones out there.
As for skills, same thing there. I'm thinking out of the box as much as I can, and here is an idea. Skills are learned through exercise of said skills. If you are wielding a pistol, and you fire, basic handheld firearms should increase (assuming you're using the pistol against a challenging opponent). This can be a simple percentage, with each slice of 10-20% representing an increase in your ability. So if I were to start a new player, and type 'skills', I would get:
-Skills-----------
-End of Skills------
Nothing. Then I equip my gold plated pistol, and kill a John Travolta. Typing 'skills' shows:
-Skills-----------
Pistols: 1% (Untrained)
-End of Skills--------
As I continue to use the pistol, my pistols skill increases. At 10% the qualifier changes from Untrained to Novice. Then at 20% to Beginner. At each such step, I become more accurate with pistols. When I hit 100%, I get a friendly message saying "Congratulations! You have mastered the use of pistols."
Now, suppose I wanted to use an experimental biologically grafted shoulder-mounted tactical nuclear warhead launcher. At first I wouldn't even be able to equip it (until my Arms/Hands stats are high enough). Now, suppose I never had 100% on pistol. I start using my launcher, and I check my skills, but I still haven't developed a launcher skill. In fact, I would only start improving on my launcher skill when I had mastered Pistol, Heavy Weapons, and Explosive Weapons (for example). Only then would the use of the launcher begin to improve my Experimental Weapons skill. Alternatively, you don't let players even use the weapon until they've mastered the necessary basic skills (they can equip it when they have the right stats, but until they have the basic skills, in combat they get "CLICK! Nothing happens. What am I doing wrong?").
In this way you can create skill trees behind the scenes, hiding them from the players, and compelling them to keep playing to reveil these skills. Partial reinforcement, they will keep coming back.

You decide whether "Pistols" will be the hidden root node, or whether there will be multiple roots, such as "Pistols" (branches into other guns), "Hand-to-Hand" (branches into sophisticated martial arts), and "Melee" (branches into various melee weapons). At each step you can make it so that in order to even gain a single percentage in a skill, the player needs to reach some minimum stats.
So how does magic fit in? Treat it separately and even more mysteriously. It's allure will be much stronger that way. Players can go on some quest to learn the first spell, pick something very basic here. Basic, but useful. I would shy away from numerical spells (healing spells, damage spells) and pick something that creates an effect, or maybe a modular spell that can do multiple things. After they've mastered it, they can go on another quest, and at the end, they are presented with a choice of one of 5-10 spells. Each one sets them on a defined spell path. Or perhaps there is more branching further down the line. The point is that they can't learn all the spells; they pick one at a branching point, and the rest are locked from them, permanently. Then you can reward people who chose the crappiest spell with the most powerful spell in the game, at the end. That is an issue of balance, but I think this would make for a really cool magic system. It is mysterious and alluring because you have to go on quests to even begin to improve it, instead of just wielding some weapon. Be creative here, but just try and stay away from turning magic into just another numerical device: a skill that changes HP/MP and spits out a line of text.
What about skills that aren't weapon-using skills or magic? I would again opt for a mini-quest/find-the-faroff-npc-trainer in order to gain that initial 1% in the skill, followed by exercising the skill in combat somehow (this can be tricky for a passive skill like dodging). Likewise, skills would branch, with a set of initial hidden roots, each one perhaps branching to another 1-2 skills. You wouldn't be able to gain the initial 1% in a skill unless you had mastered the skills directly under it.
Whew, that's all I got right now.