Given the mass of immigration to the US and all the other cultural links I think it would be better to have flights from a better variety of airports. If I was in the US and wanted to get say to Mayo or Sligo, SNN would be lousy. The same mentality exists in the UK, we have LHR what more could anyone north of the M25 want! Also I don't think mega frequency is what tourists want, convenience means a lot, being stuck in Dublin traffic for instance is no way to start a holiday.