boozee: I think they got rid of the 2ndary effects for a reason. you are asking them to go back on a design choice.
Kibou: The secondary ingredients with their addittional effects where probably removed in order to simplify alchemy, not because it was a bad feature. My idea basically is a way to re-implement the same feature in a way that suits the way alchemy works in The Witcher 2, and that doesn't make alchemy more complicated.
never said it was a bad feature, but I think you hit it on the head when you wrote they wanted to simplify alchemy :p they even went ahead and removed liquid requirements like water/alcohol :P
those design choices should answer your questions. I frankly like the potions the way they are. the tier 2 potions have enough positive and negative affects already.