People get the government they deserve, making rules to distance the military from politics wont help. Democracy (if there really is such a thing) is organic, it grows slowly until its roots are deep. Thai soldiers are citizens in uniform and yet they allow themselves to be used as an instrument for their corrupt superiors, no deep roots there, can you imagine any Northern European country in today's world where soldiers would obey an illegal order to stage a coup? No, it would be nipped in the bud and the generals arrested but not in Thailand, the subservient nature of the Thais to the hierarchy actually invites a coup.
The move is the right one however, it's a start, drawing lines in the sand but the citizens themselves must build a wall on the line themselves.