Crothian said:That's why I suggested a rising DC. So, to use the ability is a DC 10 with a +5 to the DC for each time it has been used. Sure, it adds luck into the ability but that luck goes botrh ways. The player could potentially use the ability a lot more then usual and would feel good about that luck.
In a way, that might end up with the same result as x/day, where you can rely on using the ability 2 or 3 times, but beyond that the DC gets too high. At that point, you're back in the high DC situation. From a math standpoint, you might as well go back to x/day and drop the die rolls and bookkeeping.
However, this brings up an interesting point. The "feel" of the rules is something that gets overlooked in a design. As Aaron2 pointed out, a lot of people forget to use their x/day abilities. I've seen this happen a lot myself, and some players like the idea of gambling on the ideas. It's definitely something to consider in rules design.
I'm still not sold on it as a good thing for core, defining class abiliites. It adds a random element to the game, one that makes a core, iconic party used to judge CRs and stuff by a little less reliable.
But that all said, I think the basic idea has merit.
Oh yeah, and this is all IMO of course.