Nice, I actually really like this idea with a small variation to help burn through some of the long time players TH maps AND make it theoretically possible for “newer players” to obtain one too.
Treasure Hunt: Every 60-120? Moves (developers have the data to pick an appropriate number) Players receive a random “additional bonus reward” (an arcane traitstone would be included in the list) on top of the 15 move basic reward.
Players can spend x maps before starting TH to get +1 moves in their game. So you would have 8 moves, plus your Guild Bonus, plus additional maps burned to get +? additional moves. It will still take quite some time, has a random element (like the rest of the game) and is possible at all levels with enough skill.