How about a champion upgrade that lets ground champs attack air champs(like a mounted back cannon for gorgo and lazer beams on drulls hands?) and formor just gets added dmg since hes alrdy flying/ranged
instead of paying shiny for a worker how about getting them every time you do something worth an achievementish like 2nd worker is given in tutorial, 3rd lvl 10, 4th map room lvl 2, 5th th lvl 8