I've answered this one a few times, so I'll give a shortened itemized response. 1) We added blue pill as an easier to understand way to get items faster. 2) Couriers led to team infighting when they died. 3) Couriers caused split attention to areas of the map that were not important. 4) Had complicated aspects that were not required (like the flying tax just felt like a tax). 5) Requires good pet controls that we don't have. I'm sure I missed a few, but hopefully this gives you a good idea.