I really like exalted. I've played several of the WoD games, and read the rest, but Exalted takes the d10 pool ruleset and some of the types from the WoD (shapeshifters, mages, vampires, etc) and makes them do cool and funky things. The world is neat, with the five elemental pillars and such, the backstory is engaging, and stunts are a neat mechanic that I would add to any game.
The odds of getting my game group to learn yet another rule set are low, though. We already play Hunter:tR, but the charm and essence system on top of that adds a tough initial learning curve to the rules.
I'd like to use Exaltedish rules in a d20 game. I've done some pondering, here's what I've come up with.
Key differences between the rule sets include active defense (dodge and parrying) and soak. Attack successes add to damage.
In D&D, active defense would be like giving people a dodge skill or class-based defense bonus of some kind, and rolling AC versus every attack instead of 'taking 10'. If you want to ignore that part, you can pretty easily. AC = (1d20 + Dex + BDB + shield bonus), probably.
There are good parrying rules in one of the Dragon mags, basically you give up an AoO to roll your attack roll versus theirs, if you beat it you've parried the attack. I'd probably allow everyone to have the effect of Combat Reflexes for free, ie extra AoOs equal to Dex bonus.
Soak would involve using some form of "armor as DR", maybe the rules from UA. You wouldn't need to worry about soaking using Stamina, because hps effectively replace that.
Attack successes add to damage: use exploding dice (when rolling a d20, if you roll a 20, count it as a 20 and roll again). If you beat the defender by 20, it's a critical. Beat him by 40, critical again, using normal d20 multiplying rules. For example, if you were using a battleaxe and beat the defender by 40, you'd do 5d8 damage + 5x modifiers (each critical adds 2 dice damage basically).
Weapons with higher threat ranges have that reflected by only needing to beat the defense by the low end of their threat range, instead of 20. So a longsword would crit if it hit by at least 19.
The exploding-dice critical thing works almost exactly like the normal critical hit system would if you let multiple threats happen, ie if you get a threat on your confirm roll, you've confirmed the first critical and threated for another. However, there's a side interaction with Exalted essence expenditure which I like so I'm stating it that way.
Essence: exalted have it. Assign a number somehow, or use the numbers from the rulebook, ie normal people have it at 1, exalted start at 2 and go up, 6 is godlike. Not sure how much I'd end up referring to it.
Exalted also have a mote pool, which could differ by type (Dragonblooded= Charisma, Abyssal and Solar= Wisdom), or you could use Wisdom for everybody. This could be tuned to get the right feel, maybe for Solars it should be Int+Wis+Cha. You can have two pools (personal and peripheral) if you feel like it.
Motes can be spent like action dice for any d20 roll you make, including attack, defense, skills, saves, whatever. They recover at some rate TBD, maybe 1/hour or Con modifier/hour. They work like the modifier dice from Alternity, as so: 1 mote adds +1d4, 2 adds +1d6, 3 adds +1d8, 4 adds +1d12, 5 adds +1d20. If you want to allow more than 5 to be spent, each additional step adds another d20. Even if you've spent enough essense to be rolling additional d20s, these aren't "exploding" dice. Or they could be, but limit it to 5 motes for +1d20, which can explode.
Stunt dice add +1d6, +2d6, or +3d6, by DM's call.
These extra dice work well with the "crit if you hit by 20" rule, so that you don't have to actually roll a threat to critical if you have a big stunt or action die bonus.
You can model additional things pretty well with D&D rules, for instance, Lunar DBT would be like a combination of wildshaping and barbarian raging. Sidereals are masters of fate, maybe let them spend a mote to reroll a d20 if they don't like the first roll. You can put limits on action adders to mimic dice adder limits from exalted; Lunars might limit to a number of steps equal to the appropriate stat mod, and solars to character level, for instance. Abyssals might spend motes to move their oponents down steps on the action die scale, the negative end is the mirror of the positive end.
I think it could work.