Plantwars metal

Is the only way to get metal PW via battles? The wiki tells me excessing energy gives metal and faction tooltip tells me that you also get metal from planets. But the only metal we get is from battles.

quote: PLanet ownership also gives faction 1 bonus metal per planet.

Well then that's broken. Metal is only gained from battles.

What if planets had varied amount of mexes you can build... mex on to increase that yield up to 4 metal per planet?

Mexes in game provide 1 metal income regardless of energy (no overdrive) and can be easily (say, factory's amount of hp?) destroyed.

Can be destroyed even without battle with bombers (some chance per bomber per mex to sucessfully destroy it). Costs 10 metal to build (will pay off in 10 turns).