IDK, I think Cid could very well have been a good character to have in your team. Option 1, he dies, having that dramatic impact on Celes, or option 2, you save him and he comes with you, also having an impact on Celes. As it is, if he lives, he just stays on that island, by himself, doing nothing, and it has 0 influence or meaning on the story. He is better off dieing in terms of story. If he lived and joined your party, and had his own little cut scene in the ending or something it would be nice. As a magitek engineer you could have given him the "summon" command(which is already programmed in), allowing him to summon his esper multiple times a battle, instead of the 1 limited time. That would have been very cool. Or even have him use Magitek armor for the rest of the game, and have the magitek skill set (full one like Terra). You wouldn't even need to worry about a weapon for him then.
(Yes, I have thought about it lol)
THE JACKEL