I'm afraid what I have to say initially really concerns the UK. So for any stray Brits here goes.
The whole idea of Welsh independence (they won't let me on their Forums) is, as it stands, a no go situation. Get a map and you can follow my argument. The major concentation of people, due to the industrial revolution, is concentrated in the south where the capital Cardiff is. Now look how this English speaking area is tied into English culture and English industrial dominace by the M4 Motor way. There are no motor ways to the rest of Wales. In addition the only other concentration of people is in the Noth again tied into England. The only good road connections between these regions are through England! This is in contrast to Scotland where the Central Belt is quite seperate from England
Now supose that the Capital, New Industries , Administration, Cultural Centre and Parliament were concentrated at Aberystwyth. Here a new true Welsh heartland could be established seperated from England by the Cambrian Mountains. If in addition Motorways are built to connect with Swansea in the South and Bangor in the North an Axis of Communication could be created.