In both cases, many votes are wasted and there are massive distortions between the make - up of the parliament and the popular vote so the added complexity does not solve any of the problems you set out to address. (politics.stackexchange.com)
The concerns are that this system is not necessarily «proportional» (a term which Liberal Democrats consider interchangeable with «fair»)- you can still get massive distortions of results if every seat uses AV. (channel4.com)
As I explain here, here, and here, this massive distortion pushes up the price of foodstuffs on the global grains and oilseeds market, which harms urbanites in developing countries. (globalwarming.org)