When it comes to writing sci-fi, there are lots of ways to create interesting planets that are not “one biome from Earth, but everywhere”. This perfectly respectable in soft sci-fi and may be possible for the likes of ice planets (Hoth) or desert planets (Tatooine), considering the conditions that create tundra and dune seas. They’d probably be far more inhospitable than often depicted, however.
Part of this is because so many factors go into what makes a world habitable, all of which are derived from the habitability of our own world, since it’s all we got to go off of. And our little blue and brown and green marvel is quite strange, even within in our solar system. Nothing else works quite like it does in a number of ways.
Our Moon is a conspicuously strange one. There are bigger moons and similarly desolate ones in the Solar System. Our moon is tidally locked and its gravitational effects on Earth are incredible. Everyone knows about the moon’s effect on the tides, which governs whole ecosystems, including those that likely have rise to life.
The formation of the Moon likely did more than give us our tide-governing sister. The leading theories involve vast impacts between the early Earth and another body.
These lead because the Moon’s composition is remarkably chemically Earth-like and the Earth-Moon system has a unique relationship in regards to angular momentum. This is not like Mars’ captured asteroid moons.
If formed via the Theia hypothesis’ Mars-sized body, or as a consequence of two smaller bodies colluding to form Earth (I like this one since it explains even more), several mysteries about other things on Earth.
Plate tectonics is a strange system. How it happened is a mystery. I can’t find anything that clarifies the thereabouts-timeline in regards to the system’s formation. Nothing quite (or really very much at all) like it exists on the other terrestrial planets in the system. A giant collision of some kind might have caused the kind of disturbance that results in our planet’s surface being big rocks floating about on a sea of lava.
I wonder if such a collision may also be why the dynamic internal geology (convective motion of molten iron, specifically) of the Earth never pulled a Mars and ceased all dynamism. This is why we have a magnetosphere, which functions as a great big shield that defends our planet from assorted harmful cosmic things, among other vital things.
Habitable planets are complex things, the result of so many events and systems that there is a lifetime of wonder to be found in understanding their effects. When you are creating one in a more hard sci-fi world, try playing with the effects of the factors that make Earth special and what those changes would do to a planet. What do two Moon-sized moons do to the tides? How would a ring system change things? Different mass and therefore gravity?
So many ideas!