Actually to be fair they could. A direct route from the motorway or a direct link to a main line railway that ran regularly and it would be amazing what could be achieved. A simple extension to the runway the installation of Cat 2 and 3 ( yes yes I know about the terrain) and bobs your uncle you could have a genuine transatlantic airport.
Sounds great on here, but the cost must be huge!
And there's no guarantee the airlines would come in. Might as well just start over.
Build the proposed Severn Estuary airport and uncle bob may appear!
Good location, accessible to South Wales / South West / Midlands even as far as Swindon/Reading. You can get your high speed rail links to North/South/East and West. Right by M4, road link already in place. Chance to create new layouts/terminals whether lo-cost style or transatlantic widebody style.
....We can but dream....
And.......
We'd save a couple of pages on the CWL forum carrying on the repetitive comparisons between CWL and BRS!