  The high energy physics community is discussing where investment is needed to
prepare software for the HL-LHC and its unprecedented challenges. The ROOT
project is one of the central software players in high energy physics since
decades. From its experience and expectations, the ROOT team has distilled a
comprehensive set of areas that should see research and development in the
context of data analysis software, for making best use of HL-LHC's physics
potential. This work shows what these areas could be, why the ROOT team
believes investing in them is needed, which gains are expected, and where
related work is ongoing. It can serve as an indication for future research
proposals and cooperations.
