More difficult is not the correct words in my opinion. The Thai Consulates overseas in most countries have just enforced the original laws and procedures making it seem more difficult.
The Non Immigrant O Type visa was previously issued to applicants that are married to a Thai National or have Thai Children and are in receipt of a regular monthly income, funds in a Thai bank, or an overseas bank showing and proving you can support your Thai wife and family or children.
They ask for similar requirements now that are needed for a marriage visa in Thailand or a retirement visa if you are over 50 years of age, so always check the Consulates requirements before applying.