Planetary Environmental Features

Why don't planetary physical phenomena play more of a role in online gameworlds, especially in games with science fiction settings?

There are several physical characteristics that would be fun to see implemented in an online game. I’ll use the various planets from the Star Wars movies as examples, but these ideas could be applied to any science fictional setting:

• variation in stellar systems:
• system has just one star
• system has two or more stars
• variation in stellar revolution times:
• even-length seasons (low eccentricity)
• varied-length seasons (high eccentricity)
• variation in planetary rotation speeds:
• different lengths of the day/night cycle
• different wind speeds (Coriolis effect)
• different tidal heights
• variation in planetary mass:
• different gravities
• different resource mixes:
• predominance of metals/gases on younger/more massive planets
• predominance of chemicals/foods on older/less massive planets
• variation in planetary crust motion:
• no formation = "waterworld" (Kamino)
• low formation rate = one huge, flat continent (Pangaea)
• moderate formation rate = several large, varied-height continents
• high formation rate = many small volcanic islands ("Hawaiiworld")
• variation in planetary ecospheres:
• desert:
• dry (Tatooine)
• frozen (Hoth)
• swamp (Agrilat, Corellia; Lianorm, Naboo)
• tundra
• grassland/veldt/steppe (Naboo)
• forest:
• boreal (Endor)
• temperate (Kashyyyk)
• jungle (Yavin IV)
• sargasso
• world-city (Coruscant)
• variation in moons
• different lunar revolution rates
• different apparent sizes
• different lunar appearances:
• Moon-like (cratered)
• Earth-like (moon is big enough to have gravity/atmosphere/water/life)
• gas giant occupies most of sky (moon and planet reversed, actually)
• different rotation rates:
• moon rotates to show different faces
• moon always shows same face (due to tidal locking)
• variation in nighttime starfield
• "normal" number and type of stars
• many stars (interior of globular cluster)
• no stars but bright night due to being inside an emission/reflection nebula
• no stars due to being within a "dark" absorption nebula

I've left some things out, but you get the idea: There are a lot more ways in which planets in a science fiction-based game could (and possibly should) be more "realistic." (I put the word realistic in quotes because we're just guessing what planets other than Earth and the few others in our solar system might actually look like. Still, they're the best guesses we can make currently.)

A few of these things are implemented in the Star Wars movies. The twin suns of Tatooine, the water world Kamino, and Yavin IV as a habitable satellite of a gas giant world are good examples of what might be possible. But although moviemaking has a tough time (for various reasons) with showing planets with different gravities or day/night cycle lengths or variable-length seasons, a persistent-world MMORPG could bring these effects to life though judicious programming.

Of course, the standard response is, "This isn't intended to be hardcore science fiction -- it's a game, not a simulation. All that science stuff has to take a back seat to other needs, such as story, action, etc." As someone who's been a programmer and project manager, I understand the need to distinguish between core features and chrome.

Even so, it still strikes me as kind of a cop-out for a science fiction MMORPG. Without the science -- in other words, without simulating some aspects of physical reality -- you lose a significant opportunity to give your online world a life beyond being just another button-masher game. To be blunt, "It's not gonna be a simulation!" is a poor excuse for a design philosophy for an online persistent-world game with a science fiction setting. When we have a pretty good idea how planets can vary, and -- importantly -- when those variations can increase the player's feeling of being part of a space-faring civilization, then why not implement those planetary effects?

In particular, why not add such a distinctive feature when doing so can give a game a competitive advantage in the increasingly crowded marketplace of MMORPGs?