Demand for good teachers has always been high. In fact I would say I the demand for experienced, qualified teachers has never been greater. Qualified teachers are never out of work in Thailand.
However (and it's a big however) Thailand is certainly not the paradise it once was for unqualified teachers (those that lack a degree, a TEFL certificate, teaching experience, etc) We get a large number of e-mails from teachers without degrees and/or TEFL certificates and frankly they often struggle to find decent teaching work here.
There could of course be numerous reasons for this - perhaps they perform poorly at interviews or perhaps they just haven't looked in the right places - but things have tightened up a lot over the past few years for unqualified teachers in Thailand.
As always, many employers can exploit loopholes and manage to get their unqualified teachers legal. Much will depend on how organized and 'savvy' your employer is and how much they are prepared to go to bat for their teachers.