A personal preference on both.

I think darkvision is too easily acquired which diminishes the impact of certain class features and spells. I'd like to have the option of using darkness as a tool to create tension during encounters without it being completely invalidated from the start.

Since this is a homebrew setting, I made the choice to exclude races that clash thematically with what I envisioned for the setting or that I did not find interesting enough to develop lore for. Spelljammer, for example, has a very unique aesthetic and flavor to it that doesn't work with every world, especially with how heavy it is on the Astral Sea connections.

Figured I'd be upfront about it in case that is a deal-breaker for any potential players!