Developing your skills as a deck builder and as a player is always an ongoing process, and there are lessons to be learned from every failed brew and every deck you master that falls out of favor. This Esper Mentor brew featuring Faithful Mending is a great example of taking inspiration from old decks and old ideas.
The deck I took inspiration from is the once-beloved Mardu Pyromancer, a strategy that used Young Pyromancer as a way to generate massive amounts of value in a shell full of instants and sorceries. Mardu Pyromancer also used Faithless Looting as a powerful filtering spell to smooth out its draws and to ensure that the deck always had access to spells to trigger the Pyromancer.
Faithless Looting might be banned in Modern, but the fixed version Faithful Mending is reviving all sorts of archetypes. The spirit of Mardu Pyromancer lives on in Esper Mentor.