I wonder what the English translations would have been if they had done so...
Anglesey; Bangor and Conwy; Cardiganshire and Preseli; Merionethshire and Dwyfor?
The only ones for which direct translations would work would be Anglesey for Ynys Môn (which everyone has done when speaking in English since 1983 anyway), Carmarthen for Caerfyrddin (which I imagine will be basically standard in English as well), and I suppose Aberavon and Maesteg for Aberafan Maesteg (but then the differences in pronunciation between Aberafan and Aberavon are slight). Elsewhere there's an issue that a lot of the names are odd: there are a lot of references to long-abolished local government districts and so on. There's also the very odd case of 'Brecon, Radnor, and Cwm-tawe' which is bilingual (i.e. in English the last part of the name would be 'the Swansea Valley'). There's a curious lack of consistency as to where they've chosen to use new Welsh-language names as standard: more people speak Welsh in 'Montgomeryshire and Glyndwr' (stupid, beyond ugly name there) than Aberafan Maesteg and so on. Though perhaps the very worst name is Monmouthshire, which feels like an attempt to be actively confusing and I don't care if that error had been made at local government level since the 1990s. But all aspects of the Welsh map feel like the product of profound ignorance and misapplied sentiment.
Ehrendorf's Second Law:
'The human situation, in general or in particular, is slightly worse (ignoring an occasional hiccup in the graph) at any given moment than at any preceding moment.'