I disagree re corruption, Thailand will never change, corruption and material greed are part of the genetic programming.Thus far I have met nothing but nice Thai's. I do not care their social status. North, South, East or West. Upper, lower, middle class makes no difference. If they are nice and smile I return the same. Until I started driving I had never paid much attention to the corruption but I do see and feel it now. Thai's hate it as much as we do. But like any emerging country it will take time to weed it out. This country is going to live a 'Baby Boomer" stage like the US. You have a HUGE population of young Thai's in college now. They are becoming educated and they will hit the business and political segments soon. This new era coming out will not tolerate the BS. Soon the old crusty corrupt shitbags will die and the new Thailand will emerge. Of course not everything they will change will be for the good but it will change.
20 yrs ago after settling here,I was of a similar view to your own. But all that's happened is that these unlovely traits have got worse.
There is seemingly more violence, corruption has deteriorated. and the attitude toward foreigners and even their fellow citizens has hardened as the standard of living has improved.
A decade or so ago, while it was normal for Thai drivers to be a little short in the skill department they were in the main reasonably tolerant, now even in Issarn Its fairly common to see road rage and open aggression between drivers.