The Grail, in its current form with the 5-week limit, is essentially a soft ban. After all, in 90% of cases, the game will simply end BEFORE that date. In the remaining 10%, I'm sure there will be something else to do rather than simply skipping turns with heroes, digging, and losing momentum.
Personally, I am against the Grail in Conquest and Tower maps. Otherwise, dig away.
In general, it would be more logical to move the Grail-related questions to the topic of discussing the rules of online games, come to some common decision, and then ask Baratorcha (if necessary) about something. Rather than cluttering the section intended for the technical aspects of the mod itself.
Added 5 minutes later
But who decides what should be implemented in the game? We have one game where everything is implemented :D
That's true. But it's been removed from the rules. There's value in it, but it's useless. It's inconsistent.