So I think as a whole France *experiment* in the real, dangerous sense of the term in that it's up to the individual player to show something on his own; while England already have a more limiting/guided plan for the youngsters they bring in and the insertion goes more smoothly and with less elusive/volatile effects on the long term.
While I agree England's gameplan is simple, I think the apparent safety is experimentation is more due to culture and coherency.
France spend bugger-all time together and appear to have no attachment to the national side or each other. They're playing under a coach who also seems to have no idea what sort of team he wants to play. As a result French experimentation looks to be more wild.
England in the last year or so have capped players like Yarde, Launchbury, and the Vunipola brothers all at the age of 21. The side they were brought into had/has nothing like the experience of France, but because there's a greater attachment to each other and the shirt the team is less disrupted. They're not playing alone.
If the relative inertia is lost in the backs then there'll be even more young players -potentially a 19 year-old and two 20 year-olds- brought in this coming Six Nations. They'll be around the 20-25th new caps under Lancaster in two years.