Thank you for playing !
I prefered to let the player decide if he/she feels the map is worth playing, and making it possible to reroll it easily. This is to keep some variety in the map generation. It is clear that it leads to some non-challenging maps, but I found out that some players just enjoy the chill map-painting experience :)
The problem I have with this system as it is currently is that a new player can have a very tough game due to bad luck on map generation and have a bad first impression.