True. I wasn't very specific about which Link we're pitting against our favorite Venus Adept. I think it most cases it goes to Isaac, unless Isaac is using a lesser weapon. In that case, if it's just a straight up sword fight, I think it goes to Link.
As far as characters go, I do think Isaac falls in the well above average category in terms of strength. I don't think he's near like Cloud or the DBZ cast, but he's definitely strong.
Did you just mention Cloud and the DBZ cast together? Cloud is way below them.
In the end, Golden Sun is a turn based game so we are just hypothesizing. Even in GS, the power is all over the place. The crew in GS fights enemies from measly Moles to huge dragons which crush them from space and the cast all survives.
Indeed they do not have super strength, but their elements are what makes them so versatile. It is this very versatility that puts Isaac above Link in my opinion. If we take Isaac as a good swordsman, Link might have an advantage BUT if we consider the equipment that Link has got access to, we need to consider Isaac's gear as well.
Those Djinn really, really bump up his abilities (power, speed, endurance) and we can't really scale it against a Zelda game cause the ways their games play are so different. Plus Isaac has so much he can do with Earth, that could make this fight a really, really epic one. Earthquakes, spires, giant spectral swords, vines, etc. Especially if he can control multiple at once. Plus if he gets summons, it's game over for Link, although even Meggido is enough in that situation. And against foes with lower HP (Link in this case), Meggido is a lot more dangerous.
Now Isaac vs Bayonetta, now that would be much more interesting. We can remove limiters from Isaac if he is to fight her. Mewtwo would be a really great fight as well.
Sorry if I wrote something confusing, my thoughts were all over the place.
If we're talking about Smash 4 Link and normal Isaac with all his best djini, swords, armor and psynergy than it hardly seems like a fair fight. However if you give Link all of his equipment as well then you really do have an interesting fight. You have someone who can control Earth and anything to do with it while you got someone who can literally slow down time and go back too. All i'm saying is that when you have the power to control time, then there's not a lot of things that can stop you. Not to mention he has has powerful spells of his own in the form of medallions and other such items. Power armor. I'm sorry but I truly believe Link take the slight advantage in this.
The one indisputable fact however is that Isaac hasn't done anything on his own. He's always been in a party of 2-8. Whereas Link traverses entires land masses and oceans on his own and has the strength to keep going. Even without sleeping! (I'm looking at you inns in Golden Sun)
Link wins but if Isaac had a full party of adepts with him then Link will most likely meet with a terrible fate.
Now that is just due to the genre of the game. Golden Sun is a RPG, and typical JRPGs usually have a cast of multiple characters fighting together.
I still think Isaac would overpower Link outside the balancing of Smash.