There was a 4 event season in progress.
We were at round 2 of event 3 when GAC was taken down for 1 week. Maybe 10 days?
We have restarted with round 1 of event 3, giving all players at least the losing crystals from that round, half of players the winning crystals from that round, which is all bonus for the season. Gain.
We will have the remaining 2 events to complete the season, then everyone will get the season rewards. No loss.
A player may have missed out on a division promotion, so upto 20 crystals per day for those 10 days. 200 crystals max. But other players will have avoided a demotion so they are up those same crystals. The division change can't have happened until the end of the event so this estimation is very generous. Maybe loss for 10% of players. Maybe gain for 10% of players.
The only issue is the delay. The make good easily covers any loss involved in this GAC itself.
My hope is that they will compress the time between the next few GAC so the delay is made up. As I think that they have a schedule where they want GAC to sit amongst everything else, it is reasonable to think they would do this. Net result of that in a few months: 1000 crystals for nothing but a bit of inconvenience.
Gain.