It does sound what you're arguing though. You're arguing to bring something that may not be needed, when something else could be more useful or actually needed. Let me throw in another example to augment this:

You have a party with no healer at the moment. The only person with a healing job (though most people have one by now, this is just an example) is the BST. However, said BST doesn't like playing WHM, and wants to play BST. Should they be allowed to just go BST, and have the party go without a healer? Or should that person suck it up 'cause it would be beneficial to the group to have that healer rather than going the way they want?

Sometimes doing only what you want isn't the most efficient or useful answer. :|

Edit: GG took my WHM example sorta.