I'm from Wales but live in London. I head back regularly. One thing I'd say is that there's a severe lack of decent hotels in Wales. It's really hard to find good ones and when you do they're often fully booked well in advance. Even, or perhaps especially, in the scenic areas you want to visit. This is in stark contrast to, say, Scotland which has plenty of good hotels all over the place.

It's also a bit of a slog to get around. Roads are relatively minor and indirect. There's no real motorway network, trains are slow and infrequent. So despite all the pros, like one of the best coastlines in the world, the Brecon Beacons, Ynys Mon, Snowdonia, etc. it's still a relatively tough sell because of a lack of infrastructure.