I also think this Wiki is a really good idea and would be useful for lots of people coming from Matlab.
You are perfectly right that Matlab has still a stranglehold in industry and academia partly because of the large functionality of their toolboxes, which is not available in Octave or other alternatives.
Having documentation in a single place which Matlab toolboxes are covered (not at all, partly or fully) by which Julia ones, is already of great value.
We had a related discussion in the thread https://discourse.julialang.org/t/designated-target-audience-of-julia-1-0/11804/94 where I argued along similar lines to yours why Matlab is not dead yet and why it is not so easy to fully replace it with Octave, R, Python or Julia.