Hi, there are many reasons I wanted to overhaul it.
First what you said: giving e. g. attack Blast quality doesnt mean it happens - example is not the best, because attack is actually scalable spell, so outside of my complaint, but the whole situation is what I see as a problem generally with magic system. It will increase difficulty, it will give you Strain and maybe you wont even get the effect you desire (if you dont roll Advantage) - you kinda paid two "resources" (increased difficulty - so you paid by lowering your probablity - and Strain) and even the basic success (and basic effect) is endangered. From purely gamistic view, I would prefer, if requirements (and chances, most of all) of basic effect would not change and only the modifier (Blast effect) would be "endagered". I am not saying, that original rules do not make sense - I can clearly see different approach "the more you want, the more you can fail completely", but as I described above, it just feels somehow unrewarding and from one point of view, even a bit unfair.