Nope. Golden Sun stands out in the abilities to affect the environment and to use Djinn in battle.
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Golden Sun didn't make much of an impact or growth in popularity as other Nintendo RPGs out there"
Read this to see how people still remember it as fondly:
http://www.gameinformer.com/blogs/m...4/a-reflection-on-a-great-rpg-golden-sun.aspx
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This post never made it to the blog page, so I'm going to repost it.
In 2001 a game titled Golden Sun game out for the Game Boy Advance, little did I know That this game would be one of my favorite RPG's ever. I just recently got into Golden Sun, despite the fact that it originally game out 10 years ago. I began to play the first one, when I was looking for a good RPG and I came to that one. The game was incredible and I'll reflect on the different aspects of it and how it is still great." <- Taken from Game Informer website.
This goes to show that even after 10 years, Golden Sun still has fans.
In response to underline: And? The only other RPG game that Golden Sun could have fought against was Fire Emblem and Pokemon and that doesn't change the fact that the game is still appreciated and liked internationally.
In response to bold: You see to be forgetting that Isaac uses Earth-Based Magic, something that no other SSB4 character does.
Sakurai is mainly looking for Unique characters, something which Isaac has in his Earth-Based magic.
TL;DR, you may not find Golden Sun as "worthy" as the other Nintendo Franchises, but that is not stopping him from getting in the game as a playable character. Isaac is unique, which is the main thing that Sakurai is looking for.