I can only go by the books since this is my first Witcher game and all I know Of Yen, in game, is the initial cut scene. But If I remember the books Dandelion made Geralt fairly famous, and he has plenty of power by way of just being a Witcher and possibly one of the best Witchers alive. He tries to avoid politics but keeps getting drug into it simply because of the power he wields so I am not sure how you can say he has no power or fame.
Yes Geralt would be someone that would attract her because of his power and fame, however because of her insecurities in personal relationships the very thing that attracts her would also cause endless conflicts between them. As one of you said earlier I am not sure there really is anyone that would be good for her, kind of a damned if you do and damned if you don't kind of thing.
Too be honest, if you think of Yennefer and Geralt from before The Last Wish... Well I think if you had told that Yennefer that she would be in love with Geralt and that she would be willing to sacrifice anything for him she would have laughed, she would have laughed hard indeed. And if you had told Geralt that he would ever love any woman at all he would have laughed just as hard.
But at one point in The Last Wish, he is feeling something he never thought he could feel, for anyone, ever. And she realizes that there is someone in this world that can see her for who she really is, who can see beyond all the walls she built to protect herself, see her with all her imperfections and still love her. And that moment changes everything, for both of them.
And sure this is very new for them and they don't know what to do with that at the beginning. They have a lot of issues, both of them, and they are scared, and they make mistakes. But they are willing to try. She is a powerful sorceress with a good position in life. He is a monster killer who has known for a very long time that he would be a loner and that his place was not among men. Yet they are willing to change completely the way they see things, to rethink who they are entirely, to put aside everything they ever took for granted. To be with each other. And it won't be an easy road, there will be fighting along the way, and splitting up and getting back together, but each of them will grow. Together they will overcome their fears, and whatever may come they will face it together.
So you're right, kind of. No one is good for Yen at the beginning, because of her insecurities, her fears... There is someone however for whom she is ready to change.