With the right carrier, offering the right schedule and prices, people from the Southwest will find CWL an attractive option. Maybe not the preferred option every time, but if the price is right at the time.
There's talk again of improved road links from the M4. 5 mile lane is apparently getting upgraded, although I've not seen the plans for that.
Let not forget the large amount of leakage to other Airports from the Welsh catchment. For South Wales originating passengers CWL is only 20 mins off the M4 and most people wouldn't chose not to book from CWL just because of the links.
No-one knows what the likes of QR will do to inbound tourism but transport links will need to be looked at soon. The rail link could do with being improved, maybe Arriva could look at extending the Merthyr-Bridgend service to Swansea at least. A bus service to the West is also required.
CWL's growth is nowhere near the likes of BRS and other Airports, but it has a lot to prove and a long way to go to rebuild confidence of travellers and Airlines.