Yeah the photos of that look pretty good. It's a shame it didn't go ahead.
With the current terminal it depends on what the Welsh governments vision is. It is entirely possible that the current one could be upgraded through revamps of the boarding piers especially the western one and by expanding the check in and arrival areas and by even adding an extension on as there is plenty room between the terminal and BAMC for that.
My personal opinion is that in the long term the Welsh government will look at a new terminal but to do that they'll need long term investors as politically I don't think they could get away with such a large outlay of money.