Biggest problems are quality of build, size of plot, neighbours and noise and security of relationship. There are also sharks out there ready to prey on the unwary some of the worst are fellow expats. Be careful buying anything with police involved it's gets expensive. Rent for short, less than a month or so holidays, it's cheaper in the long run. I would not buy in a touristy area, though I have bought and sold in Hua Him, they overdevelop like crazy, lack of parking and pollution end up ruining places, like Hua Him and Pattaya, Phuket etc
Thai visas are generous compared to many countries. You apply for a visa, you break the rules, what did you expect, congratulations. Talk about a sense of self entitlement.