Why does the author classify Hamon as (less) extreme center ? It's been more than a decade that Hamon was the left barycentre of the PS. Man has always taken example of the South American left and he actually got axed from the previous government because he found it too neoliberal.
Anyway I think one of the shortcoming of Mélenchon's campaign which wasn't really talked about was (like Sanders) that even though he's an honest man, charismatic and a great speaker, Méluche is 65. That's still 10 years younger than Bernie

but that's quite old nonetheless as he was the second oldest candidate this elections. I think him and Sanders share the same qualities but also some cons that mostly (only ?) revolve around their "grand" age. In 2022 Mélenchon will be 70 and I hope for the sake of his movement that he will groom a younger candidate because it really feels that he'll be too old. Since 2007, the candidates have been younger and the old generation has slowly been erased (finally !) which is good because in France in our "congressmen" are usually elected by 55 and are mostly around 60 and 70 and our senators are even older.
Mélenchon is now the figurehead of the French left but IMO he should slowly preparing his exit. Considering he was close this year, he may feel like he could win it in 5 years but if runs in 2022, this should really be the last of his runs.