Re: Macron wins....
You don't have someone like Le Pen take power unless there is no other alternative. The time isn't right. Between now and the next election though who knows?
It would be wonderful if Macron does stabilize France but I think this is an impossibility - he is an EU creation after all, and the very fact Le Pen has done so well is because of this very fact.
My worry is the EU will push through all sorts of rules - laws - on everything that can play into Le Pen's hands. In other words smother news in all sorts of ways (it is already extremely biased) or stifle dissent by making certain criticism illegal - another step up from the tactics the PC Brigade use now. Pretty sure they will push something through quite quickly in an attempt to disarm the affects of immigration.
Someone like Le Pen taking charge in the future is a possibility if the troubles that affect the people who voted for her party now spreads to the those that voted for Macron. This could happen if the EU (and France) merely continue on the same path as they have until now, and lets face it they intend to.
In my opinion France and Europe are heading for something hardly worth thinking about.
A good country to study how views can change after suffering duress is Sweden. Slowly but surely they are changing their minds about being so liberal minded.
Many only learn through hardship - a lesson learned, and some don't even then. Scary stuff.