by Vee » 11 Jan 2015, 12:29
Mathematically if you ignore range and pretend that damage is applied in a continuous fashion rather than in discrete shots then the strength of a unit is dps*hp: a unit with a higher dps*hp will win against a unit with lower dps*hp. Suppose you have two units fighting each other, having dps1, dps2, and hp1, hp2 respectively. Then the lifetime of unit 1 is hp1/dps2 and the lifetime of unit 2 is hp2/dps1. So if you want to know who dies first you need to compute the minimum(hp1/dps2, hp2/dps1). We can multiply and divide by dps1*dps2 to get minimum(hp1*dps1, hp2*dps2)/(dps1*dps2). So you see that who wins depends on hp1*dps1 vs hp2*dps2. So we could say that hp*dps is the strength of a unit.
A similar argument shows that dps*hp/mass^2 is the strength of a unit if you also take cost into account. If you compute that number for various units you'll see that it's very consistent: even very different units with vastly more hp or dps still have roughly the same dps*hp/mass^2. Of course in practice range and speed and how bulky units are matters so much that this theorycrafting is useless for actually playing the game.