IBZ was great in the summer peaks - could have filled a 747 June to Sept. But you need 352 day routes out of smaller bases.
SN Brussels airlines charge upward of £300 for BRS BRU if you want midweek at shortish notice. I've seen their 146's depart with 12 pax and their commitment varies wildly between thrice daily to once which hardly 'builds' the route.
Amsterdam is a major easy base with a large number of rotations and built in ground support. Adding BRS seems quick and easy.
Rome was tried and chopped. Still think there might be a market for it - there is a suprising number of Italians settled in South Wales and the West Country plus is really is a kicking city. Much more fun than the Barcelonas and Pragues of this weekend break world.
As for other people already offering the routes. I don't recall Brymon shifting 750 one way seats a day out of BRS to Scotland..? Offer the seats - and they will come...
Cheers,
WWW