The french league may not be that great, but lets be honest, la liga is getting weaker as well.
Just look at the state of Atletico, who is in 2nd, or RM in 3rd, these are the two best teams in the league after Barca? Really?
La liga is better than the french league, but the gap isnt as big as people like to believe, mostly due to la liga getting weaker.
The gap is still important imo because the lower spanish clubs are better technically.
However, la Ligue 1 is not as easy as they say here because it is a very physical league. Neymar has said so, even Jesé has said so. And as football is a sport, the physical side can't be overlooked.
It is also the reason why english clubs like to poach Ligue 1 players : they are very rapidly able to cope with the premier league physicality while having more talent than the usual english players (maybe not true for the new wave of english players). And players in Ligue 1 are showing it is not that harder to be good in la Liga like Lo Celso (considered best transfer of the season ?), Guedes is one of the best player of Valencia, Gameiro was a good player at Sevilla and Atletico, Ben Yedder at Sevilla, etc.
The only real problem of Ligue 1 though is money, but the same can be said for portuguese or lower leagues like dutch one. Once you have a decent player, he can be bought without much resistance by their clubs, simply because they are overwhelmed by the financial might of other european clubs.
And it will take time to develop a better economical context for the whole french clubs (that spends way more money than any european counterpart on taxes).
For example, Lyon has a good strategy for the future being the only club in top flight with their own stadium. Usually stadia are properties of the city. However, they have huge difficulty to fill their stadium and end up giving tickets for free (and still, it is not full). PSG would have no problem to fill a bigger stadium but there is no place to build a new stadium in Paris and the current Parc des Princes can't be demolished and rebuilt and can't be remodeled.
About the goal coefficient, it has always been the same for the top 5 leagues. Why is it a problem now ?
I remember, not too long ago, Ligue 1 was known for being very very defensive with a lot of 0 - 0. At this time, no one was complaining with the goal coefficient, while other leagues like Germany were known for being heavy on the goals. Now that they are more goals in Ligue 1, it has suddenly become an issue for some people...
To stay on topic, and without surprise, Mbappé said again he will stay with PSG next season. It had already been said by the journalist close to his family : Julien Maynard.