if
it's about Cardiff..
Sport, Entertainment, Transportation, Business,
Development Projects, Leisure, Eating, Drinking,
Nightlife, Shopping, Train Spotting! etc.. then we want it here!
I think that if such arenas (with an appropriate rate of return for the private investors)were so bankable, then we would have had one by now, be it in Bristol or in Cardiff.
I can therefore only conclude that they aren't (without a sizeable input from the public purse), so (if the public purse strings are restricted), I'm not holding my breath for any announcement on one any time soon.