Oh, please...
One file—ONE FILE, out of 925 of them—and she's "dead." Now that's overreaction.
This is hilarious, and she's interacting with Kogoro—KOGORO—that's never happened.
If you compare Shiho/Ai from her intro to the end of the Vermouth arc (Files 176–434/Episodes 129–345) to her after she rejected the witness protection program (Files 435–437/Episodes 346–347), she's different. She no longer contemplates suicide, and is far less abrasive than she used to be. She's actually gotten to live a normal life, and it's changed her. She'd never be able to act like she is, now, in the BO—no chance. That threat may be hanging over her, even after her death has been faked, but it really has lessened... she can relax more, now, than she ever could in the past.
If you're referring to this as the culmination of a buildup since she rejected the witness protection program, and claim that she's been put to the side, effectively, then you're right that Gosho hasn't let her do much since then. But with the series still having a long way to being over, jumping the gun like you are and making this extreme assertion... that's unwise. Heck, the point of this story, for her, may be her not being such a fangirl, when it comes to Ryusuke. Even if it isn't , though, I'm telling you... just wait.