The event was announced weeks ahead of time, giving players some time to prepare. It's possible to get everyone in your corp/alliance to fight together on a single side, so queue-syncing is much easier to pull off. The rewards require effort to acquire and it's possible for the average player to reach the 20 match minimum.
The event also got people to really put time into faction warfare and it seems like many groups will continue to play it. Dust and EVE players are also reaching out to each other to work together. The rise of faction warfare as a much more competitive environment has allowed players to go full blast without the guilt of proto stomping. Anyone going into the warzone knows what they're in for.
With no long term consequences, there's no reason for anyone to be loyal to any side. By itself, this wouldn't be so bad. In conjunction with the prize system however, you've got some real problems.
So each reward tier requires a certain win rate to obtain the prototype level gear. This alone would be fine, but with the game's current meta favouring certain suits/weapons/equipment, the strongest people will naturally gravitate towards the best rewards. In this case, most of the top players went Amarr. So what did everyone else with no loyalties also do? Joined Amarr.
I suppose it's my own fault for picking Minmatar, but the repair tools and mass drivers looked so nice. There were a number of groups playing Minmatar with some success, but why would the average corp pick the losing side when only winners are rewarded? CCP tout the "you're a mercenary" line when it comes to loyalty, but it's almost silly how one sided this all became. How CCP use the data from this event will be as interesting as how the playerbase interacts with faction warfare going forward.
Overall the event had some cool ideas and a good effort:reward balance, but favoured those who picked the winning side. It was interesting to watch play out, but I hope they try something different in future events.
p.s. Some more heavy rewards would be nice in the future.