Quote from Lunchguy
The idea of using fire charges was only because it makes it use something other than things dropped from the mob used in the recipe. This is so that you can't just camp a blaze spawner and be able to make a giant blaze army.
Well, I have other things set in place to prevent that anyways.
You need a doll to be able to craft a blaze in the first place, and dolls are rather rare. Since the dolls are consumed in the making of the mob, you can only have as many mobs as you have dolls.
The way I see it, you would be lucky to get just one doll, they would be as rare as apples used to be when they could only be found in dungeons.
You also need XP to create the mob, that prevents any abuse of the system as well, though I suppose you could just make and XP grinder to get around that.