Justice is a fan-made global mod.

Swordsmen in the seventh installment are a tribute to similar units in Heroes 2, placed on the highest tier. In my personal opinion, as an exception, "minor" units can be given high tiers. Dark Elf witches, for example, are not ordinary citizens according to the lore, but rather matriarchs who essentially manage the clans. They can be portrayed at their level (especially since they are among the weakest at that level). Another question is how huge and impressive hydras with regeneration ended up on tier 5. I fully support moving them to tier 7. Monks are probably another case – specifically because of the training, as you described. It's hard to imagine that any man, even for money, could be turned into a hydra killer... And paladins violate logic for the same reason. In general, human training has always been lore-specific.