You've really latched onto this Aladine pun idea, huh? Don't get me wrong, I like it, it's clever and it works well in a series like One Piece, which basically runs on puns.
But what wonder is, would it read the same if we didn't already know the name was meant to be pronounced like Aladdin? The _din_e in sardine is only pronounced the way it is because that's a french word we've adopted. On its own we'd read it with a harder I: die-n, as in, fine dining instead of deen, like sardine. If he was a sardine fishman I'd be strongly inclined to take your side, but with a brotula there's nothing to contextualise the pronounciation except the broad world of fish.
Is it impossible that Oda intended a pun in English that only works with French pronunciation? Hell no, anything's possible and we know Oda has more confidence with western languages than most manga authors. Do I personally think it's likely? Nahhh, sorry, Oda's good with languages, but not as good as some people would like to think.