Changing the alphabet is not an extra-planetary idea: The Turks have done it once, the Azeris a couple of times and some of the central Asian countries have changed alphabets three times over the past hundred years. The Russians tidied up their alphabet following the Russian revolution. The Spanish have changed the status of ‘ll’ and ‘ch’ in their language and these are just the examples I know of, I bet there are hundreds of others. Even the English managed to drop two letters, though that happened a millennium ago.
I am not a linguist but I have been baffled by whether the Welsh have completely got a grip on which letters are actually in their alphabet. It is an issue that has been a struggle for the Cymry ever since they tried to systematize their language and someone came up with the idea of these double letters. I am amazed WAG hasn’t set up some quango to deliberate on this ad infinitum et nauseam.
I like the green and red colour scheme (but will it faded quicker? and how will the colour blind cope?), but the different typefaces is a second rate idea borrowed from the Gaeltacht in Ireland. They have a folky italic typeface for Irish, though less retro than the one used for Basque in France. Overall as a designer, he has done well to get us thinking. We definitely need some new symbols because road signs in Wales are getting wordier and bigger!