I maintain it is inefficient. Mostly because I don’t like it. I don’t like it because I think it is unclear emotionally and in what it is trying to tell viewers. That makes it full of stuff that is unnecessary imho.I'm afraid I don't see the inefficiency you're describing, but we may be thinking about it differently. I'm thinking of saying as much as we can in a single sequence, since we already have so many scenes in this episode.
An individual just falling overboard seems more like a manufactured accident to me, especially if we have to also have him lose the palantir out of ... his pocket, I suppose? Also, it seems to me to make Amrod look clumsy and careless rather than making the Feanorians generally look like poor sailors.
This does not actually do anything concerning setting up the Feanorians as poor sailors, for one thing. It also risks inviting the audience to see Amrod as a bully victim and a whiner, rather than a sympathetic character who has a good relationship with his twin brother. Not to mention, Amrod is less likely to be honest about how he feels with Caranthir than with Amras. Finally, it seems unlikely to me that Caranthir would through away something so useful. I feel like he would be more likely to give it to Feanor (or even keep it for himself) instead.
Someone falling overboard is less manufactured than a whole ship capsizing.
Supposing Amrod dropping the palantir out of his pocket is just silly, of course. Did you think that was my idea?
The story about Noldor being bad sailors is frankly uninteresting to me and something I’d rather not see in our story. Yes, the Teleri are master sailors. That doesn’t mean the Noldor are bad ones.
The idea of Caranthir throwing the palantir away has problems, sure. He doesn’t have to know exactly what Amrod is doing with the palantir and when he wants to know, Amrod could be secretive about it. He could struggle with Amrod trying to take it from him and a movement of the ship could make them lose their balance and drop it in the water.
Or we could lose the palantir altogether. But I do like that element of your idea. Sadly, it’s obscured by a capsizing ship.