Resources:
Overall the resources cost differences for humans on upgrades is not always a win especially since in most map gold is more valuable in the long run yes you do not have to bother putting more peons on wood but you will run out of gold slightly faster too so overall not a real win
ok will start here... u dont need as much peons for tier 1 is what i emnt ok so when u tech faster at lets say 16 15 peasants.. u have like a45 second speed advantage .. once u tech u pull 5 out mine an chop .. leave 10 in the mine ... then u make 2 peasants add them to wood as ur makin a stable u do not rep the stable.. once stable is done u go castle .. then once castle is done u spam more peasants put them on gold... an of make 2 mage towers an a church.. by the time ur done wit this ull have about 7 knights 2-3 mages and holy vision all befor a orc hits lust.. id say thats a huge advantage not needing as many peasants
and ps ... u dro pa early mill for wood advantage an use the peasant u made the mill with to chop early so he will pay for ur stable.. the others will pay for your castle.. sometimes i move more from gold to wood wood to gold depending the situaiton but its all about resource management gettin the resoureces when u need it ... so hu has a huge speed advantage an it doesnt affect your gold in game