Even with the aforementionned problem, it's always a compromise between two options.
The risk here is something rather serious but has an extremely low probability of occurrence.
The downside with having the dome light on (even dim) is having reduced crew night vision. So a much smaller risk, but every time.
How many times did the complete lighting failure occur, among how many flights ?
I would have assessed that before asking anything about dome light on.
Never heard of dome light on takeoff at my operator (up to 150 320s were used)