These are have been mmo ideas popping around in my head for years. Away from button mashing and more toward a game that rewards thinking and preparation over fast twitch. Everquest was the only MMO I know of that directly translated a players knowledge and experience into ingame effectiveness to any extent.
I'm aware its just me, but I really want a game that moves away from archetype classes. Why can one person swing a sword and another cant? Why can one person do magic and another cant? There hasn't been a good MMO that explains that in the context of the game.
Maybe one day there will be a game where anyone CAN do anything they want, its just the limitations on practice and preparation that limit them. Weight allowance is a great tool for this. Stop allowing people to carry dozens of weapons and multiple suits of armor. Also make magic much more difficult, burdensome and powerful. For example two players gear out for a dungeon crawl. Player one has been working his melee/tank type skills. He has been crafting his armor, learning move combos, increasing his strength through runes, potions, and practice. He is a good tank because of actual training and experience in game.
I would like to see players learn melee skills in actual move combos, somewhat like a fighting game, but not that complicated. Focusing mostly on putting together efficient and effective combos of moves predicated by weapons used and fighting style. Any melee COULD do anything.. but why would a 6'10 tank work jab combos with his broad sword and shield? Players would learn moves in game and they would be unlocked by various means.
It would be up to the player to use whatever ones he wants, in whatever style, most effectively for what he wants to do. Basic examples for a sword and board warrior would be: Thrust; high/low/middle (low damage, high speed, high hit probability, low effort, med taunt, maintains defense) Cross Slice; Vertical/Horizontal (High dam, slow speed, high effort, high taunt, opens defense). Low Cut (low damage, med speed, med effort, low taunt, med hit probability, maintains defense, +movement debuff), High Cut (High Damage, Slow Speed, High Effort, Low Hit Probability, med taunt, +Crit/Kill Shot bonus)
These basic attacks would be paired with a defense that included how they held their shield (max protect, most effective vs large creatures, heavy attacks, -damage for attacks, some attacks not available from this this stance; Dueling Sheild (+damage, -defense, all attacks available + special shield attacks).
There would also be sword blocks, mostly simple stuff that would ask the player to anticipate what attack is coming, (high, low, mid, Overhead, left/right flank) Successful blocks would allow for special parries or ripostes and lower defense of opponent. This would really open up dueling and make pvp much more interesting.
Magic would be another beast. I would put a heavy emphasis on the magic user being prepared to use magic and cast certain spells. Enough regents, focus objects, materials. Wearing the right equipment (i.e. not plate armor) like robes that can hold these materials and augment power. Casting a spell would be like a mini crafting skill. It takes some time, it takes some preparation, it has variables... but it can be fucking devastating..
Id even like to see an interface for casting like the game Black&White from Lionshead, where you had to make certain symbols to cast the spell while holding certain objects with your mouse, and the more precise your drawing, and better the regent, the more effective the spell. A spell casters abilities would depend on what materials they had, what spells they were had memorized and practiced, what they were wearing.
Anyone could do healing, or Damage, or necromancy, as long as they were prepared. More powerful spells would have high demands and be more complicated. There would be no shitty high level mages.