after working with corona7 now for a while, i find it a bit odd, that you named the old/standard corona-material into CoronaLegacyMtl.
I constanlty run into errors with various scripts etc, that won't recognise coronaphysicalMtl which might became the new standard.
would prefer also for compatibility issues, that the old material would still be named without "legacy" ... as the differentiation is already done with the addition of "physical"...
also the new corona-converter is a a bit odd... as it only converts materials into the new physical-material... there seems no option converting it into the "older" legacy-material...at least not for the seleted objects i want to convert.