And in doing so he shed his countryman's blood. I agree that he was a good king but he took everything from Skellige by force. Traditions, Jarls and made Skellige a monarchy. He are the sentences from the game.
''In Skellige, anyone can be king. All they need is the jarls on their side. Sometimes a mediocrity gets just that. And the isles get a ruler they don't respect. No one expected much of Svanrige of Tuirseach. But he went down in history as the founder of a dynasty. And as the king who united all the clans against Nilfgaard.''
This paragraph compliments him. But now watch this part.
''Many islanders believed Svanrige would be no more than his ambitious mother's puppet. The young king proved them wronng, ignoring her whims and ruling with an iron hand all his own. Tired of the jarls and their endless feuds, he resolved to turn the isles into an absolute monarchy modeled after those of the Continent. What he resolved, he achieved, but only by shedding his own countryman's blood.''
And the last sentence says it all. Would you rather have Cerys. A queen who looks after her land and people for the first time in the isles. Or have Svanrige who attacks Nilfgaard while his people starve and die.
Even if you want to fight with Nilfgaard, first you must have a country that is capable of it is at its full strength. Not when the country is in the worst state it has ever known. You are choosing the king or queen of Skellige, not of Nilfgaard. There's no need to attack Nilfgaard now. First you must look after your own land, then turn your attention to your foes.