I don't think there should be a new skill, by I definitely think changes should be made. The problem is, fish has the 3 main things going for it: Convenience, good xp, and usefulness. This leaves only two options, either change fish, or bring in new food to make. The prior isn't going to happen, to I wont delve into that, but the latter is what Jagex is trying to do, unsuccessfully thus far. The have released many new food options, such as the dairy products, baked potatoes, and new pies, but what they are all lacking is convenience, and to a lesser degree usefulness. Until jagex creates a food item that is easy to make, and heals a lot in one bite, fish will remain at the top of the cooking skill.