but then news articles are not renowned for their accuracy
More accurate than the average PPRUNE posting, I would wager....
Be careful of assuming that Thomsonfly from CWL is a low cost airline. The Cardiff operation relies on selling off rump seats after the charter requirements have been met, so their pricing model tells us very little about the dynamics of the Cardiff market. Also, when you see their 767 departing for PMI, don't assume that aboard are 300 happy punters who would have flown baby/easyJet/A N Other Jet - most of them have bought Tui packages, and had no choice of carrier.
an upmarket service is not what is required from CWL
A rather broad generalisation. BA ran Club Europe services from CWL to CDG and BRU, at about £500 return (J class), and the many times I flew it they had very promising loads in Club, which had a min fare (D class) of about £375....
Cardiff does need more routes, and many of those routes need to be operated by low fares airlines. However, there is certainly room for premium carriers at Cardiff as well, provided that they are advertised properly and have sensible fare structures, and are run on the right size aircraft. IMHO, Eastern only got the last of these three things correct.