Argument
There are a few ideas that should be implemented or at least should be explored.
These features will impact the other aspects of the software as it impacts other areas such as editing and file translations.
Multiple Premises
More than one copy of argumentative may be
Evaluation
This is a very grey area.  Some system of weighting needs to be applied as well as some level of validity.
Evaluation is also referred to as analysis in other systems.
Evidence
Evidence may be mentioned in comments
Co-premises
Co-premises are one or more helpers that have the same importance as the reason or objection they are supporting.  The system needs to handle the helper in tandem and equally.
There is now a definition on Wikipedia for Co- premise to help the process along.
There will need to be some extra functionality added, not just display changes.  Two reasons or objections should be able to merged into co- premises.
Supposing that for the sake of argument...
A method of indicating reductio ad absurdum argument. See http://en.wikipedia.org/wiki/Reductio_ad_absurdum for more detail.
Schemes
Argument Schemes, also known as Argument Schemas and Argumentative Schemas are a pattern of argument. These schemes help form valid argument as well as help identify fallacies.
Three schemas are put forward by the Araucaria project:
  • Walton
  • Pollock
  • Katzav & Reed