They need to fix two things before I'd part with a satang in income tax here:
1) Firstly, apply the same rules to your own citizens as you're trying to do to expats. When every single working-age Thai has a TIN and files an annual tax return, then I might consider doing so too.
2) Taxation is a two-way street, if you want to take you need to give something back in return. So, for example, anyone who pays Thai income tax should NOT be treated as a long-stay tourist but as a permanent resident, with the right to own land and access the Thai healthcare system if they want to, and no tedious Immigration reporting or annual visa renewals with all sorts of bells and whistles attached.
As the situation stands, they're trying to take expats living here for suckers, applying strict rules for foreigners and extremely lax ones for Thais, milking pensioners for all they've got and giving nothing back in return. More fool you if you're willing to accept that.