This removes some of the meta-game "I can only do this trick once a day" from 4e martial classes. Instead of having their powers rationed on a per-day basis, now they rely on chance to get the opening needed to use a given exploit.
"Encounter" exploits become "Common" exploits, and "Daily" become "Rare".
Assign each Common Attack exploit a number from 1 to 6. These cannot overlap.
Assign each Rare Attack exploit a number from 1 to 6. This list can overlap with the Common after you run out of numbers, but not with each other.
Assign each Utility exploit (be it common or rare) a number from 1 to 6. The common and Rare may not overlap.
At the start of each turn, roll one Utility d6, one Attack d6, and two Rare d6.
If the Attack d6 lands on a number for a Common Attack, you may perform it that round.
If the Utility d6 lands on a number for a Common Utility, you may perform it that round.
If the Rare d6 lands on a double, you may perform any Common exploit (utility or attack) that matches that number this round.
If either Rare d6 lands on the same number as the Attack d6, and that is the value of a Rare Attack exploit, you may perform the Rare Attack exploit that round.
If either Rare d6 lands on the same number as the Utility d6, and that is the value of a Rare Utility exploit, you may perform the Rare Utility exploit that round.
Characters may burn an Action point to reroll some or all of their Exploit dice at the start of their turn.
This results in, on average, being able to perform your Daily/Encounter expoits slightly more often than you could normally (presuming a 4 encounter day, with 6+ rounds per fight) -- except now you rely on luck, and cannot trigger them exactly when you want them.
You can use 1 red attack die, 1 white utility die, and 2 black rare dice, to make the rolls quick. Keep a table of number -> common/rare attack exploits, common/rare utility exploits, and it shouldn't slow the game down much (it might even speed it up!)
If a class has more than 6 utility exploits, put the overflow on the common/rare attack exploit table. Abilities that can be used twice per day or twice per encounter should have two entries. (This applies mainly to the Warlord, whose class features provide utility encounter powers).
At-will powers remain at-will.
If you find this is too restrictive, allow Martial characters to pick two powers for a given die slot instead of 1 when they gain a new rare/common power. They can then pick either of the two exploits (but only one of them) when the result is rolled. I don't know if that is needed, however.
The main problem I see with this is you lose out on a lot of choice and tactical capability. You jsut roll the dice to see what you're allowed to do this turn.
I think for this to work, all of the powers would have to have their own trigger. Like, when an enemy hits in a certain way, or when two enemies move in a certain way, etc., and the trigger could be something "common" or "rare" by virtue of how frequent it really is.
Gives new meaning to the Rogue, Ranger and Fighter classes, don't it? :)
And yes, it means that you are living by the roll of your exploit dice. Some powers (such as tiggered interrupts) should probably stay daily/encounter based or be utterly useless.
Oh: and reliable exploits gain:
Miss: you may use this ability next round.
The dice are supposed to represent "openings" for doing the move. As D&D combat is relatively abstract, it doesn't cover "your enemy moves his sword down and to the left" level of detail, or "you get really pissed off". ;-)
Isn't the unpredictability of combat exploits already handled by having to roll to hit? You decide to use a Daily Exploit, and if you don't hit the enemy's AC, you lose the power. That does the job of ensuring you can't depend on an ability working at the right moment and creates situational and tactical possibilities for other players to help you succeed, even by using their own daily powers to buff your attack roll.
The idea of Once-per-day powers for a Fighter doesn't really make any real-life logical sense. Perhaps the easiest way to think about it is that if a PC decides to use a power, it's actually because in the game world an opportunity has arisen for the character to use it.
Using the core rules is perfectly fine. Some people have expressed horror at the idea that "Rogues have a per-day ability?! That makes no sense!"
So I crunched some math, and generated a relatively simple to use system that removes "per day" and "per encounter" restrictions from Martial characters. Instead, openings for exploits are determined randomly...
Anyways, Martial classes are the few classes that shouldn't rely on luck. You could say that someone saw the caster begin to cast, and started to get out of the way, but the martial classes are supposed to have narrowed down their skill to a point where they will do anything that might catch the enemy off guard. This is just makes the martial classes go back to the "I hit him with my sword" style. Besides, would you travel with someone who seemed to use their skills randomly? No matter what the situation was?