During 3 months after adding the serial resistors I caught garbled display only once (without the resistors display was garbled every few minutes).

If I was designing a new controller board, I would further improve LCD interface, but there are a lot of other terrible things in cheap 3D printer electronics, like MOSFETs driven directly from controller outputs, endstops with NO switches, or electrolytic capacitors placed directly under hot stepper motor drivers.
So taking into account all these potential problems, I would say that 1 LCD error during 3 months is acceptable for me.