Purple side matters because Purple side is at a visual disadvantage.
Also, I don't think that ARAM is very "random" either.
Due to all the people on these boards that say things like; "4 games is hardly enough to draw conclusion from", I keep track of the ARAM games I play.
Based on more than 300 games, I can say, with data to prove it: I am rarely on a team with one than 1 ADC, while the Enemy team usually has at least 2 adc plus a Ziggs, Morgana or Katarina.
I own 74 Champs.
If we break it up into two groups, 1) Top 10 champs I'd like to play and group 2) 10 Champs I'd least like to play.
Champs I like have a less than 1% chance of being rolled, while Champs I don't like have a 10% or higher chance of being rolled.
In a sample of 100 games, I rolled ZAC 7 times!
While in the same 100 games, Maokai, Leona, Amumu, Irelia, Braum, did NOT appear at all. Rolled 0 times.
Champions I don't own have a higher chance of being rolled than any of the top ten champs that I'd like to play.
I've played a total of 50 games since Mordekaiser and Zyra were placed on the "Free Champions" list. together I've rolled them 5 times. That's a higher than 10% chance of being rolled. while, again, the champs that I would like to play appear 0 times during that span of 50 games.
As I look at my database of over 300 games, seems to me pretty apparent that ARAM is NOT Random at all. Its almost as if the game uses an algorithm to roll champions that you are unsuccessful with and dislike. Leading to an overall dissatisfying experience.