Imagine if each slice in the Advanced output had a blend mode that could be assigned, effecting the way in interacts with the slices beneath it that you could selectively place as part of your mapping. This would be a blend mode workflow akin to After Effects.
Currently I find that the blend modes of layers + clips lend themselves more to 'fullscreen' content or more traditional VJing, but I find myself not using them as much in scenarios where I don't want that much overlapping texture; desiring to use blend modes more decoratively in specific parts of the installation.
This would be a major task to implement, no doubt. Maybe there is a workaround for this that I haven't realized.