Yes that mutation point is interesting - as far as i recall SARS just stayed SARS the whole way through. I assume nCov is itself a mutation of an existing virus but don't know if it's likely to mutate again - and whether that mutation would make it worse

As for the acceleration rate, the death toll is roughly doubling every day - it's now up to 104. SARS killed 774 so its on track to eclipse that in three days if it keeps going at this rate