If you really want to go for realism, it's pretty likely that a hypothetical sentient plant would eat other organisms like animals do. Photosynthesis doesn't produce nearly enough energy to sustain intelligence, and really there's nothing stopping a plant from being carnivorous anyway if it needs to be. Farms would still make perfect sense.
We don't know that photosynthesis doesn't provide enough energy to sustain intelligence. That's an idea too restricted by Earth biology and our local star system.
Maybe they didn't evolve around a G-type main sequence star? Maybe it's a star with a much higher energy output? Or their version of photosynthesis is just a hell of a lot more efficient than Earth plants, using something different from the Krebs cycle? Maybe they metabolize shorter wavelength radiation for more energy? Speaking of which...
The "Outsiders" in the Niven Known Space universe soak up radiation on their sub-light travel between the stars to metabolize. They're basically highly intelligent, mobile, spacefaring plants that act as intergalactic Traders with secrets and technology to sell. There are many other possibilities like this, once you get away from Earth-bound thinking about biology.
And ideally, that would make the way you play them in the game different as well, not just a skin for existing gameplay.
- 3
- 1