If TG were to get their act together and refurbish the 77E in J to lie flat seats, then there should be minimal disruption. Don't know how long it will take for them to upgrade the aircrafts. Have not heard if any of those upgraded is already flying.
TG does not operate with safety margin to cover if something may go wrong. They just put out the fire as the fire comes. The RR engine issue really makes life difficult for them. But as in everything in Thailand, this too shall pass, so what is the problem?!