The thing is we know she exists and the writers are probably trying to keep things realistic. Think about any couple of married co-workers, not Danny and Lindsay. They wouldn't be huggling and talking about their baby all the time.
सी एस आई is a procedural show, which means personal storylines are not to be the main focus of the show. Some become relevant (ex.: Flack's grief, Danny's injure), but the cases are always the most important part of the show. Actually, personal storylines become important many times because they're टैंगल्ड with cases.
Lucy is there, she is relevant because she has altered Danny and Lindsay as characters and she has radically changed their relationship. However, why should she be दिया any और screentime? Unless they intend to play the cliché "baby gets kidnapped" formula, there isn't much time left for her. There are already too many loose ends, especially this season, and episodes can't be longer than they are now.