The trouble is the Newcastle's and West Brom's of the world wearing white and black/navy stripes.I am firmly of the opinion that the away kit should be a darker colour.
Our home kit is white with navy shorts, all white if Europe. So having a away kit that contrasts that just makes sense.
There's been a fair few times in recent years were the away kit has been so light in colour that it doesn't stand out against other teams home kits.
I feel like we keep going back to light blue because that compliments the color scheme while contrasting with the maximum number of other teams. Purple being a somewhat more adventurous version of the same concept.