So why must gnomes be shorter clones of elves? Seriously, we already have elves that worship trees and kill people who chop them.
Why must Good regions be lethal at all? The point of them is to be more hospitable, not to murder your dwarves or make them useless.
Well, the point most people are trying to get across is that dwarves generally aren't a good-aligned race but usually (lawful?) neutral, not taking the actions of the player into account, and as such would most likely be considered invaders in a good region. Besides, we also already have the Benign/Neutral/Savage distinctions on top of it to allow for further variation.
If one where to settle a good region and not cut down any trees, dig up the ground too much, hunt the wildlife etc, you'd probably be accepted and not set upon by its magical denizens. Generally though, most players playing normally would upset the magical forces present and should suffer as a result. In a benign good region (Serene) there shouldn't be that many dangers. But a savage good region (Joyous wilds) should have you beset by Ents, Unicorns, Satyrs etc if you disturb the peace, in my opinion
Then again, arguing over how to interpret the "good" part of good regions is kind of moot since they'll most likely be revamped into the sphere alignment regions before any major changes are done :>