RAAS is good, in fact excellent. Unfortunately, basic human factors tells us that the hearing sense is the first to suffer exclusion in times of high workload and/or stress.
IMHO RAAS probably isn’t strident enough to attract the attention of someone completely fixated on landing the aeroplane (which is probably a major causal factor in overruns) and “xxxx remaining” needs a bit of mental processing before the import is known, although it might work for the PM. In contrast, there’s a “whoop whoop” on the GPWS and it virtually shouts to get attention, windshear comes up big and red on the instruments and fire warnings are unmistakeable both audibly and visually.
Maybe we need a flashing runway overrun light in the windscreen or a buzzer in the seat or something...