I teach RCIA, and last year, during the Easter Vigil, we lost power inside the Church for the majority of the Mass. Fortunately, we processed in with candles (and there were a few backup lights on the walls, but not many). I must say, this was a moving experience, as it turned out. Kind of like the old days, I'd imagine! Perhaps we will plan to keep the lights dim more often! But you are right, the ritual should give the indication of going from darkness into the light.
Regards
Last year we processed into a darkened church with candles after the blessing outside. In years past we sat in the darkened church and passed the flame from candle to candle.