There was some discussion about the show's ending in the previews thread for the most recent revival a few years back. As with this thread, there were a few interesting takes on various sides. Below is some of what I said then, as I still pretty much have the same perspective:
"The Little Mermaid with racism" was pretty much what Rosa Guy was going for when she wrote the source material novel, 'My Love, My Love'. If anything, I have wondered if the musical sanitises those elements a bit too much. There seems to be a bit of a tonal mismatch between the somewhat brutal original story, and the (largely) joyous, charming vibe of the musical.
I think some of the discomfort I feel about this show also comes from the way in which it presents a false dilemma for Ti Moune between unhealthy love, and unhealthy hate/death. Ti Moune has to either keep loving jerkface Daniel 4evah, or outright kill him. It's rather depressing that she loves him to the very end, and that some of the show's lyrics present this as a triumph: "Ti Moune...proved that love could withstand the storm...and survive even in the face of death!" Not the greatest message for any young people in the audience. The original novel, IIRC, more unambiguously portrays the Ti Moune character's undying love as the tragedy it is.
In the moment of truth in the show, when Ti Moune has to make her love/death decision, I wonder if it would work for her not to say "I can't... Daniel, I love you!", but rather something like "I can't... I won't harm him the way he has harmed me. But I made a deal, so take my life if you must." That way, Ti Moune stops playing the gods' game, and both gods lose their callous bet: Ti Moune's love (rightly) hasn't survived, but she has also (rightly) not brought death to Daniel. This would be further removed from the novel, but perhaps more suited to the hopeful tone of the musical; what should bring hope is the survival of Ti Moune's goodness, not of her love for an a$$hole.
(I do like the show by the way, most days; I just think it has its flaws.)