This essay is much more useful in understanding politics than anything Umair puts out. Unfortunately, Umair makes a middle-class living with his work; Erik does not. This says more about us than these two writers.
PR systems have their flaws. Erik described --quite well--the "balancing act" PR parties have to play by to gain influence. How to get votes from parties close to you but not annoy those parties is very much a Machevillian approach.
This essay also plays with various political terms. These terms are often fuzzy and any attempt to better define them tends to lose the spectators. As well, Erik describes how long-term parties have actually evolved with time. Sometimes this evolution goes beyond their original fuzzy name. Political parties do evolve--and voters should not look past 20 years when casting their vote.