People who have played the games first probably subconsciously project their experience with "Triss, the romantic love interest" onto her book counterpart, ascribing more importance to her role and generally attaching more value to the scenes she's in. Which is understandable, even if it slightly distorts the actual text.
Which leads to the aforementioned 'Player Agency', which works its way into every aspect of an RPG's story (if well written).