Fourthly, An EEA family permit is nothing like as strict as a UK Spouse visa, and it is issued quickly without the exhaustive evidence that a UK Spouse visa application requires.
Fifth, A UK spouse visa would not allow benefits including GP/Housing/Income support etc. for at least 2 years: whereas an EEA family permit allows your wife to work full time immediately or claim benefits in the unlikely event that one or both of you fall ill or hit bad times.
Six, Affirmation to Marry at the British Embassy in Bangkok costs 3600 baht whereas the Affirmation to Marry at the Irish Consulate in Bangkok is 900 baht.
Seven, The EEA family permit allows visa free movement across Europe for your wife under the Schengen Agreement, whereas the UK Spouse visa does not, as the UK is not part of the Schengen Agreement. If she gets a UK Spouse visa she will need to get a Schengen Visa every 6 months to travel almost anywhere in Europe which is a real pain, especially if it is for a short trip.
Eight, Labour have just announced a language requirement for new entrants. This means that your Thai wife needs to speak, write and read english up to a good (GCSE) level before she applies. This is coming in within 100 days for UK spouses which again is not easy!! Under a EEA Family permit this is not required.
Anyone that says getting a UK spouse visa is easier doesn't know what they are talking about.
And last of all, try
http://www.thailand-uk.com which is a site dedicated to Thai people living in the UK.
Good Luck to you and the Missus