I think the problem with the dingy lighting is partly because it’s so irritatingly mismatched. The shape of the Voyager ceiling doesn’t help with the dark wood (cigarette stain) panel running down the middle, along with the curved overhead luggage racks which also creates dark spots.I do find it funny when people refer to the Voyager saloons as dingy whilst other threads have complaints about the 'dentist's chair' lighting on e.g. IETs and the new/refurbed Northern units. I prefer the dinge.
I am able to time my commute so I only get doubled-up Voyagers on quieter days of the week for less than 50 minutes and from that perspective they're alright. Admittedly that is a small fraction of the overall experience on them.
An IET for example has a more square interior profile with clear glass racks which takes away some of the dark dingy spots.