One thing that strikes me about most academic knowledge tools is that they seem to focus on parsing the current set of academic literature and producing supposedly interesting insights out of them (which quickly tends to snowball into wanting some kind of generalized model for knowledge as a whole). What I think is much more interesting is creating tools that help people create better academic writing in the first place (thinking tools if you will). This is however much more a UX problem rather than it being a pure engineering problem. That is why I think we see many more tools in the knowledge extraction space as most academics thinking about these kind of things probably have an engineering background. That combined with the the fact that we seemingly all want to throw machine learning at any problem we encounter.