I was thinking that it would be useful if there would be the possibility to create effect tracks and send audio tracks to them. For example if you would have three different tracks and you would like to have the same EQ on all of them you could just send all the three tracks to one FX track with one EQ. And in the same way as top layers in Photoshop don’t actually change the layers under them the effects on the FX track wouldn’t actually modify the three underlying audio tracks. If at some point you would realize that some effect isn’t that good you could just delete it from the FX track, or modify it.
It would also be useful if you could add effects to a single audio track to some slot at the same place where the solo/mute/gain/pan options are. The effect would apply to the whole track and you could modify the effet or even delete it which would return the audio track to it’s original state.