Not sure if other LA stations were clamoring, but it is no secret that KTTV has languished in the mornings for years. To take a popular talent from their direct competition (KTLA) and bring them on to their morning show speaks to them trying to change their fortunes in the ratings department. Don't forget KTTV recently acquired Stu Mundel from KCBS/KCAL. Stu was their popular nightside chopper reporter known for his animated coverage of police pursuits. KTTV is making moves to be competitive.
Not sure if KTLA wanted Michaela back. The morning A team they have now with Frank, Jessica, Mark and Sam works well for them. When Michaela left KTLA, I was one of the doubters on Jessica being able to fit the news anchor role well as she was previously the PM weather caster with the late Hal Fishman and then moved on to AM entertainment/features reporter. She has definitely earned my respect. She does a good job in the anchor seat.