There is a reason they have taken over- it's because they are better.
I certainly agree!
A few days back, during a night approach on a non-standard 3.9° ILS in montainous terrain the lighting system was very much dimmed. The papi was dimmed that much that all four lights appeared to show red.
The problem as I see it...
The white light of a white/red PAPI system is too close to the colour yellow/orange and this results in inadequate contrast with the red lights.
The problem with the dimming of the "standard" bulbs is the heat produced with the power available. These bulbs generate only the correct and designed light (colour) when operated at the nominal power.
A quick call to ATC to increase intensity will solve most, if not all, of the issues mentioned.
The problem is that a light pointed at you at high intensity, giving the correct and expected colour spectrum, may disturb you during the approach; a dimmed lighting, as perhaps requested by a previous aircraft, may give you the expected 2 white / 2 red only on short final.