the card system doesnt have stats, all units cards dont show stats!, is like playing league of legends going to the store of items to equip the champion and buy something when i dont have stats on what im buying, it would take hundred of hours to know the stats of an item because i cant see the stats until i buy it, instead of right away before sending it.
I dont have time to search on wiki
Come on!
when i goto buy something on the store of lueague of legends, all items have stats and all info needed 
but when going to the home city shipments, i only get this: 
what ottoman improvements?! come on!
how much is increased?, what are the stats of surgean? how much a hospital built by a surgeon cost? how many heal a hospital per second? as you see league of legends would give all info on his item store, but age of empires dont. No wonder why ive never send many of the cards, because it could be only lose of time
honestly i think this info about card was done by a very lazy guy, no wonder why aoe3 is not so popular.
Maybe all this was done in purpose, but thats a very bad idea for the game. We need numbers in order to take decisions. We need to save time, not waiting to the card arrives to know what it gives.
a shipment of natives? how many 5 10 15 per native post?
info about cows, how many per second do they fatten out of and in a livestock?
basic (without bonus) stats for ronins,
all this should be posible to see with just some clicks on the home city
how much food would be with “additional 150”, 200food eac cow??
this card system needs more info so its not highly critized because takes hudnred of hours just to know what each card does