I think leaving legacy base sizes is actually pretty important, and better to add/leave that stuff in over deleting that information.
If some models have that missing, it's really not a good reason to delete additional information - especially if the purpose of the article is to be useful over looking elegant.
This is especially relevent when talking about the models that have been more recently migrated to entirely new base sizes and formats. 40mm>60mm is pretty straightforward, but 40mm>75x42mm is a much more tricky thing to try and sort out.
(yes, I have a huge pile of old Tyranids and other models still unbuilt!)