Mrs Swing ~
You didn't say what length size (or girth, if that's equally important) is disappointing to you, but I think it would help to mention that here.
I see no problem with mentioning in your profile what size penis you want. I've seen a number of profiles mention this and am thankful they do. It lets us know if we should take the time to contact them.
Also, on the ad site we use it has a place for men to list their penis length. Men don't have to give this info, but my husband chooses to because this way we don't worry about that being an issue for people who contact us. They know the score.
I consider penis size like any other preference. If it makes a difference to you, you should let others know.
LM
BTW - I've never encountered a penis I didn't like. I guess I'm a lucky lady.