Taking a contradictory line for the sake of argument, having no run off areas would mean grass? a wall? gravel? I’m not sure any would have changed Senna’s particular angle or impact significantly.
I think they do overall, make circuits safer, but they bring the thrill factor down and the need to be so cautious about a turn incase you go over the limit and drop it.
Ultimately, it’s the strength of the cars that save the drivers these days imho. The one clear factor that hasn’t changed massively since Senna’s death is the amount of wheels that go bouncing around the place. That’s much more a danger than the impact from the walls it seems, because it’s an uncontrollable factor. However I think there are 2 tethers per wheel coming in for 2012, but not this year ( correct me if I’m wrong ), due to the redesign costs.
Personally I want to see the RB X2010 prototype racing around in an exhibition league. But that’s not likely to happen unless some sheik somewhere decides he’s fed up of looking at all his money and needs to be a bit more flamboyant than buying another pimped up Ferrari, or building another glassy curvy tower somewhere on the desert that remains 90% empty for the next 20 years.