Yeah, mostly because she being kept would've fixed some issues from TASM2 (but not all, obviously).
For example, Aunt May needs Peter to get her car from the shop for her work and that's the last we hear of it. With the MJ stuff, we see Peter go to retrieve it and get it but it breaks down to where he meets MJ on a motorcycle who offers him a ride due to car troubles.
She'd also meet Gwen in the film and be Peter's next door neighbor. Also, her abusive home life is touched on and Spider-Man even confronts her father, too. She worked as a waitress during the Rhino/Spidey battle and they kept one scene of her in (where her back is to the camera as she watches Rhino cause destruction from inside the coffee shop).