Events have always been a good way for players to catch up by obtaining tokens for weapons, battle marks for ships, etc. Alternatively, if a player was in no urgent need of these things, he could aim for unique cosmetics. Once the event ended, or if you missed the event entirely, you could still grind things like battle marks and pirate tokens in the base game; you’d only be missing out on some cosmetic options that didn’t effect gameplay.
Adding an entire ship that is exclusive to the event is, in my opinion, a bad move. It will discourage all players from grinding for other items until they’ve obtained the ship due to FOMO.
In addition, the fact that this event focuses around Amber, which forces PVP, means that the more established players who already have strong ships and groups of buddies to help them will be able to more easily grind for the new ship. Rather than the event being an opportunity for people to catch up and even the playing field by earning a lot of battle marks or coins to buy new ships of their choosing, this event sounds like it will be an aggressive dash to the exclusive ship which will no doubt be powerful to justify the grind.
In my opinion, the new ship should not be exclusive to the event.