With today's engines and gearboxes having to last multiple races + limited boost on the turbo there is no way some extra fuel is going to give these cars insane power. And with the limited downforce they have now I wonder how much use they could actually make of this extra power. The only thing where more speed is really going to be more "dangerous" is in the high speed corners.
Also with regards to safety, does it really matter if they take a corner at 200 or 230kmph?
You might not be aware of this, but the cars are already quite a bit faster in a straight line than they were last year, reaching higher topspeeds. At this point, it's any ones guess how much power these engines are producing, even under the fuel flow limit. You are also mistaken in your assumption that there is a boost limit - there isn't - which means that if you didn't have a fuel flow limit, these engines would be capable of producing a lot more power. You don't need to take my word for it - take the FIAs:
FIA said:“Giving the same amount of fuel to each car is an easy way of promoting efficiency – but the requirement is not as simple as that.” said Lom. “With no other limitations we might see some extreme and dangerous powerful engines, coupled with exotic strategies.”
“The fuel-flow limitation is there to stop this, enforcing a certain level of control. I say ‘a certain level’ because the engineers working on this project have an infinite amount of ingenuity, and over time the will certainly develop more efficient engines with greater power output.”
Source
Safety isn't only about the race either. It's also includes qualifying and/or practice where the cars aren't limited by the 100kg per race rule.