Rationale -- the product that my working life revolves around -- currently has three mapping "modes": grouping; reasoning; and analysis.
Reasoning mode is for loose informal reasoning:
To tighten up the argument I use analysis mode, which allows me to break out the hidden premises:
Grouping mode allows me to create tree-like structures for non-reasoning purposes:
So while the reasoning and analysis modes provide specialized support for argument mapping, it is grouping mode that one turns to for all other tasks. I.e. Less sophisticated = more general.
And through the magic of our powerful "morphing" facilities it is possible to start working in one mode and then have Rationale convert the map into either of the other modes almost instantly. Very useful when you find yourself in the wrong mode!
So what's the missing mode?
In fact, it is possible to do reasoning in grouping mode, just without quite as much constraint as in reasoning mode, because fundamentally both of these modes manipulate "tree" structures.
What's missing is a mode which generalizes analysis in the same way that grouping
generalizes reasoning. Let's call this new mode clumping or clustering.
I am not quite sure what the applications will be, but I am confident that they will emerge.