I was thinking more about the direction and size of the light source, actually (with contrast coming in third). I can always throw on a cut of CTS or CTO to get a near-match to the predominant ambient, and that, too, gives me a known colour temperature so RAW processor presets (or batch applications of adjustments or stored camera profiles if I'm using, say, a Color Checker Passport) can work just fine. The flash makes the diffeerence between taking your subjects to where the light is "good" and making good light happen where your subject happens to be. (Completely killing ambient means losing the context, which may be a good thing or a bad thing.)

A more sensitive and efficient sensor may make portable continuous light sources more practical in the field (modulo photon shot noise — no sensor can make light a less probabalistic phenomenon), but it doesn't eliminate the need to make good pictures under sometimes unfavourable circumstances. And unlike the stereotypical landscape photographer, an event photographer can't just pack it up and come back later when the light is better.