I couldn't agree more with this. Note that most of these videos are of the vehicle up close, where warning really isn't that important. You want distance warning. Try one of these "all split heads" vehicles at 500' or something, and they'll appear to be basically a steady burn light.
One thing that most people overlook is dark time. Flashing lights flash to give activity, but for activity to actually happen, the light has to go ON then OFF. Most people think about how they can make more light (that ambulance with waay too many lights, above, is a good example) but forget about dark time. If you have no dark time, then it's a steady burn light.
A good, steady flash pattern at a reasonable rate (not 320fpm or something) is the most effective for recognizeable, distance warning. For stopped vehicles (at a scene) the rate should be much slower (60-120fpm) than when en route to a call. COLOUR does not get people's attention, ACTIVITY does. In your peripheral vision, you don't see colour anyway, but are extremely sensitive to movement. So, for intersection warning, you need lots of activity in a bright source, but colour doesn't really matter. The WORST thing you can do for intersection warning is depend on colour and have little activity or intensity. That said, warning to the rear is a completely different story.
The split heads, especially the smaller ones, don't meet SAE Class 1 when flashed in split mode. For example, a 4-LED head may meet Class 1 when all 4 LEDs light up at the same time, but won't meet it when you split flash them because your peak intensity is not high enough because you are flashing only 2 LEDs at a time, which is not enough for SAE Class 1.
That said, lots of customers ask for a split red/blue because (for police) they want to be "recognized as a police vehicle". For me, I really don't care what they think I am, as long as they don't hit me. I'd rather be visible and mistaken for a fire truck, than unseen.
If you have split lights, try viewing them from a distance and see what you think. I'm betting you'll be surprised at how poor the warning is.