Wouldn't that merely be a spiritual continuation of an already undesirable feature, concerning that rats and other simple mobs are truly not very different in RP on offer in the slightest? Lizards are, in effect, slower and stupider green rats.
Having to chase some little shit out of the kitchen by throwing knives at it - whether it's a normal rat, a green rat or any other kind of rat - is not desirable gameplay for me as a chef. Nor is chasing something with the OOC intelligence of a human around as a janitor, especially when that something is played with the sole purpose of pestering people.