Events are a neat idea that was very poorly implemented.
Becalmed and Mermaids were both massively game-breaking against any fleet that wasn’t specifically built to avoid them or at least minimize the effect. Players started “unofficially” banning them in games almost immediately.
Favor of the Gods, which wasn’t released until two full sets later, was nothing more than a Band-Aid that became almost mandatory to include in builds if there was even a remote chance of an opponent using one of the other events. At the same time, because it was assumed that all opponents would have FotG, that in turn made players far less likely to use those other events because they’d be immediately nullified by something that cost less. Unless it was known for sure that opponents wouldn’t be using events of their own, players more often than not tossed it into their fleet builds “just in case”; it was better than the alternative of needing it but being caught without it.
Hidden Cove worked well during playtesting, but the wording was changed at the last minute from “previously explored” to “unexplored”. Instead of the nice thematic effect of letting a ship quickly return to somewhere it had already been, it became a teleporter that instantly sent one of your ships to an island loaded with treasure… and not even FotG could do anything to prevent it.
False Treasure is a nasty effect that could potentially swing games, but the 10-point cost made it completely unplayable in anything close to a standard (40-point) fleet build. Even in 100+ point games it’s difficult to justify.
Duel almost worked, but it needed some serious limitations, particularly on ranges, and probably point limits too. There are enough high-value crew in the game to make Duel an auto-win against more common but still essential crew (especially captains), which made it way too overpowered. The fact that you could pull it out and hit someone all the way over on the other side of the table, with almost no way to defend against it, made it even worse. Maybe limit it to targeting other crew within L, and reduce the bonus to something like +1 (only) to the player who used the event and/or at most +1 to the more expensive crew, making it far more thematic but also much more risky.
Rolling Fog was… meh. It was mostly just a way to burn a leftover point if you had literally nothing else to spend it on. The effect was fine, but because it was completely random you really couldn’t use it for anything meaningful. It would have been far better as an additional (or optional) effect for the fog terrain itself, making them work more like icebergs. That, and/or give the player who placed the Event full control over where that fog bank moved.
They aren’t all bad, though. Divers provides a cool bonus for sinking an opposing ship without breaking the game, while Raft is a good way to kinda protect important stuff from being lost if an opponent gets the jump on you. It can at least buy you some time, maybe.
Cursed Zone always had some really interesting tactical uses both offensively and defensively, but you definitely had to plan around it, and the ever-looming threat of FotG meant you couldn’t rely on using it for very long.
Foul Winds was more annoying than useful, but in the right circumstances you could catch someone off-guard with it and maybe disable a small or heavily-damaged ship that thought it was in a safe place.