Interesting interview here, mostly the bit about Jeff Tracy: https://m.soundcloud.com/rossironfield/vfx-producer-sharon-lark-talks-about-thunderbirds-are-go
In the interview, the producer talks about how it's all about the rescuses and as least violent as possible.
Guess we won't see a repeat of some of the events from the original series which involved what today would be deemed acts of terrorism (passenger aircraft being crashed in the sea, bombs on board aircraft, hijackings etc).
It's funny I never really considered Thunderbirds violent, what with The Hood, and some other characters, always surviving the most ridiculous of crashes and such. At least not when compared to the more direct violence of Captain Scarlet:
Captain Scarlet was never as widely accepted as Thunderbirds and may also have been critised for it's violence with scenes like the above.
And I don't think Thunderbirds even with gun fights etc was any more violent than a lot of kids shows.
Though I think when it comes to hijackings etc that's probably sometihng we've become a lot more sensative to over the past 15 years,