Biggest problem has to be the way the rallies were run, looking at the crowd control (or lack thereof) in mainland europe and southern america, shows you just how lucky they were to have as few fatalities as they did.
Inevitably the cars would have become much safer year on year (group s was on its way, with 300bhp max), but some of the rules back then do seem a little strange nowadays. For example aeroquip hoses were not mandatory on the cars so all teams (bar one, toyota?) used standard hose and hose clips to save weight.
That said, it was my Dads group b videos that gave me my love of motorsport, just amazing to watch