Is grand arena opponent selection totally random?

It’s not random at all. You are drawn in a bracket with 7 players directly adjacent to you in Skill Rating. 

Then it does not reflect GP or other parameters which relate to rooster strength. Skill or no skill, there is hardly anything you can do if your units are totally overwhelmed, spare for maybe taking out their weakest team with your strongest to lose gracefully. 

Except that if someone was consistently winning at a given Skill rating their SR would improve and they would advance to face stronger opponents. 

You've facing the people you do bc you put more effort in. If you face a 14Mgp opponent when you have 2M gp, they still have to lose 1/2 their battles to stay there, which probably means that half the time they don't hit at all. So take out their weakest team with your strongest and then enjoy your win when they don't play at all. 

Except that if there are more than 7 players with the same Skill Rating then it is completely random.  Or at least there has been no explanation. 

So what you're saying is that it's not completely random at all, but is controlled by skill rating with ties broken by RNG. 

The word "completely" does have meaning, you know? If there are 500,000 SWGOH players and 11 match your skill rating, your GAC cohort isn't "completely" random. Possibilities are hacked from 500,000 down to 12 through non-random processes before the tiebreakers. 

Except that for most people it is more than 12.  Just picking the kyber 3 leaderboard

https://swgoh.gg/gac/leaderboard/?division=15&page=1

When I last checked those leaderboards were the status at the current seeding.  So, at the top of kyber 3 there are 80 players with a score of 3309.  Then 3308 goes from 81 to 166, so 86 at that skill level.

For all intents and purposes, how those 80 at 3309 and how those 86 at 3308 are then put into brackets of 8 is "completely" random.  It is pure rng after it gets to this stage.  The word "then" has meaning.  

nottenst wrote:

For all intents and purposes, how those 80 at 3309 and how those 86 at 3308 are then put into brackets of 8 is "completely" random. 

It's coding so it can't be random...............unless they've actually installed a cryptographic Random Number Generator to handle something that really doesn't need to handled...............so extremely unlikely it's random.  Most likely, the coding has some hard rules it follows to place the players in a determined order.

Once that happens we're matched with players who are next to us on the ladder.   

In short (I like to use adverbial phrases too), I highly doubt there's anything random about it.  I'm sure if somebody could be bothered, they'd find the pattern.  

From the outside looking in it is random.    No one has ever explained it.  I've seen some people pose a theory that it is by ally ID.  

In a thread well over a year ago I was able to prove it wasn’t Ally ID or Player ID.