I can't be the first person who finds that getting more crew members is the brain-dead obvious first thing to focus on, am I? I've played a few times, and tried to pretend it's not true, but it seems that it is. The top priority is to get as many crew as possible before they run out. If anyone can suggest why that's not true, I'd love to hear it. Maybe if the game were played to 4-5 buildings instead of 8, I could see it. But with 8, there's plenty of time to do other stuff once you max out your crew.
Given that, I am thinking there's needs to be a counter balance based on crew size. Options I'm thinking of (all untested yet, I'm just brainstorming): 1) Resting only rests 3 crew. 2) When hunting for treasure, there is a tax of half your crew size, rounded down, plus the 1 gold printed on the board after the tax. E.g. 5 gold in the treasure is worth the same 5 gold to someone with 3 crew, but only 3 gold to someone with 6-7 crew. 3) Your crew + wood + fish is limited to 15. 4) There are 3 hammocks below deck. Resting a 4th (and subsequent) crew member injures them instead. 5) Your Nth crew member costs an extra (N-3) gold.
I've won a game where I bought 1 crew the whole game and once where I bought only 2 crew. We also had somebody come in last with 8 total crew. The thing I think is the most broken is the building that reduces the cost to buy other buildings by $1.