Care to do a redistricting project with Welsh-size seats everywhere?
I tried to do the opposite. I nearly cried
I can also imagine the chorus of Welsh opposition to having their valley teamed up with another or having a huge rural seat in the middle that pays no attention to anyone. Still it can't be worse than the f-ing Dumfriesshire, Clydesdale and Tweedale seat (and I don't care that the Tories hold it!) amongst others that the Scots were saddled with.
As for creating a map of the UK with constituencies of a Welsh size; that would be task in itself and would fall victrim to urban gerrymandering.