Nope. Any series rarely (if at all) manages to succeed after a change in demographics like that, especially if violence is part of the series. It's like saying "We need to make Warhammer 40,000 a PG series".
Anyone who is remotely familiar with Warhammer 40,000 would know that would likely be the death kneel of the series, as the process would gut a major component of the series. Same with Fallout. Fallout without six, death, and violence numbs the "humans are outright bastards" theme that's prevelant through the entire series.
"War. War never changes." Why is this the arc words of Fallout? Because people never change in that universe. Underneath all the trappings of civilization, humans are still that same violent, primal ape from the opening scene of 2001: A Space Odyssy. And changing the series to "T" would deaden that core theme.