Wouldn't Slime be the corporate choice if anything, literally used for all marketing where as Erdrick would be just for fans of the games he was in. I doubt that Erdrick would have wider appeal than Slime would just for sillyness alone.
I would think so, but corporates have told me in no uncertain terms that men with swords, cars or guns are more marketable than
A) women
B) animals
C) psychologically backed up symbology
D) actual multimillion dollar toy liscences that I got a spoken agreement about using
Corporates have a very different idea to the fandom... And that's kind of why prior to 5ch the fandom had kind of settled on Slime as a real cool guy.
As for Cloud and Link I would only argue in a game with Pikachu and Mario wouldn't Slime make more sense, but I don't think itsuch value to argue about what makes sense as honestly Sakurai can make anything make sense with work.
Sudden pertinent thought:
I admit Nintendo are better at getting their audience as a market, selling breath of the wild with a massive vista on the box art for a game that is selling to it's fans as a giant open world to explore. Or there's Odyssey with various colourful locations on the box in a game sold to fans as being the return to dense thematic worlds to jump around.
Final Fantasy XV was sold to fans as an open world and grand narrative. So what did they put on the box for the wider audience? Four men with swords, guns and a friggin car!
I know they're the main characters but that's not the best way to show the appeal of the game, it's a way to tick boxes for what suits think sell things. And that's why I think the dude with the sword would be the corporate choice, because the appeal of Dragon Quest is mostly in it's charm and comfort... Alongside a well balanced turn based system and a bunch of exploration, but mostly the charm. Slime is the way you portray that, but it has fewer men or swords so it's probably not marketable or something...