I have just done my renewal and it has been streamlined.
You need to pass an online test, photocapture the acknowledgment of completion.
Bring expired licence.
Medical certificate, got mine at Thai Inter in Chaweng, eye test included.
Face page from passport, signed.
Visa page from passport, signed.
Licence office is upstairs now, you can go any time. Present your documents, do the Depth, color and reflex tests.
Pay 505 baht and done.
I was in and out in 20 minutes.