Is this siege weapon - monk bonus a strong one?

I wonder if I create a civ with the following bonus:

"Siege weapon can be healed by monks but can not be repaired by villagers"

Will the civ be balanced? Will the army of monk and siege be that strong compared to saracen or aztec etc ... Other things about the civ: full monk tech, full siege upgrade, above average economy bonus, average infantry and naval, bad archer and cavalry.

Thanks for all the replies