Yeah, roadcourse safety has improved leaps and bounds since Senna, but there are still a few really dangerous corners- the kink at elkhart lake for one. 15 feet of grass before you hit concrete.
There are already the typical "is indy racing too dangerous" questions (front page of USA Today) that always crop up when someone getsa killed and that usually don't amount to much action.
I really think you can place some blame with the sanctioning body though. Offering $5M to any non-regular who wins is only going to get you a bunch of guys who may or may not know what they're doing. Rumor is that the drivers complained that speeds were too high in practice but the IRL did nothing. When these same drivers complained of the same thing 10 years ago at texas motor speedway, CART called off the race and pissed a lot of people off, but protected their drivers.
There's a reason CART didn't have these types of accidents, despite going faster. IRL will keep hurting/killing drivers until they figure out what that reason is.