The penalty for going wide should be measured by the effect on the car. It shouldn't need discretion or video reviews and the like.
Back when, track limits were defined by high kerbs, strips of grass, huge pits of gravel or the occasional wall, drivers respected the limits or faced problems.
It was made even worse in Bahrain by the slightly confusing application of the stewards discretion. I fully agree with Brogan that overtaking outside of the track limits is always going to be rightly penalised. For the rest of the race, at one point Verstappen queried about cars running wide in turn 4 and was told that no one was being told not to and to carry on doing it unless told otherwise. So, when even the drivers are unsure what interpretation to apply and when, it suggests an issue.
There must be some sort of ultra low grip surface that can be used for a a few feet around the edge of these more modern tracks that have huge areas of run off which would be safe to have but prevent this track limits issue being a problem.