I just want some clarity into the ratio of "how much an immobile unit is worth" to "how much a mobile unit is worth", all else being roughly equal.
For these comparisons, I'm assuming EVERYTHING about the mobile and non-mobile versions is the same (cap, cost, range, damage, shots per salvo, etc) except for speed.
Unfortunatley, the ratio varies WILDLY based on the other stats.
If the mobile version of the unit had a very long range, high base DPS, and was already sort of slow, then maybe I would only consider the immobile version to have about 1/3 "utility".
If the mobile version of the unit had a very short range, poor base DPS, but high speed, then I would consider the immobile version to have around 1/20 utility, if that much...
Yes, the ratio of utilities can have that huge of a range (though I would say it would never get beyond 1/2 utility ratio, even in the best case)
Basically, when losing mobility:
Range: higher means less utility lost
Speed: higher means more utility lost
Rate of fire: higher means less utility lost
Base DPS: higher means less utility lost
Durability: higher means less utility lost
Resource Cost: higher means more utility lost (though this is a minor impact to the "ratio" compared to the others)
there are probably many other factors too, but those are the big ones I can think of.