I'm an experienced RPG player and I found the introductory "Fort Joy" chapter daunting. My fights were lasting 30 minutes or more and I came out of them feeling the opposite of refreshed. I finally turned down the difficulty to its lowest setting and managed to squeak by the shipboard battle after a couple of tries. Then I got to Driftwood, and haven't had one difficult fight in several hours of play.
I would like to suggest that instead of making Fort Joy so difficult that it turns off the average player, you let that serve as a lower-difficulty "get acquainted" stage, and allow things to get a bit tougher later, after the new player is hooked. I think you'll have better retention that way.
I'm not sure what stats you accumulate but you might look for early dropouts vs purchasers to confirm my theory. It's a worthy game, so I'd like to see you prosper!