Can anything one wants to do with schemes be accomplished with single-step reactions?
+ Can store multi-step reactions together in one logical datatree. Data about the entire scheme is stored directly with the scheme (as opposed to under one or more of the single-step reactions).
+ Simplifies linking of single/multi-step reactions.
+ Abstracts multi-step searches to a higher level in the toolkit (invisible to programmer).
- More complexity in tools and databases.
- Potential to confuse the database view: most likely for both single-step and multi-step reactions to be stored (there is data about both).
- Implicit schemes are still required for searching (explicit schemes don't eliminate any of the 'work' that we must do to search).