The Paradox of Rhetoric

Aristotle's rhetoric is divided into three general categories: logos, pathos, and ethos. Is this sort of debate rhetoric outdated? Should we still strive to excel in all three categories? 

The paradox of rhetoric is that in trying to convince an opponent, we have to appeal to all three rhetorical devices. However, in doing so, we open ourselves up to criticism. For example, an appeal to authority might be futile -- "just because you have the credentials doesn't mean you're right". In fact, your opponent, who has just pointed out your appeal to ethos, might use it against you in order to label you as untrustworthy and crooked depending on the lens through which they view your credentialing. 

However, only appealing to logos might also have its issues. One might come off as blunt -- and even rude. In fact, one could argue that logos alone does more to insult than convince. For example, take the catchphrase "facts don't care about your feelings". Whereas the phrase itself is mere rhetoric, it emphasizes the logos of one's argument. Might logos come off as too blunt and do the opposite of building rapport with an ideological opponent who you are trying to convince?  

Thus, the paradox of rhetoric goes as such: In discourse, should we be appealing to only logos, or also to pathos and ethos?