You're not going to get anywhere with Apple because I'm sure they feel that Ken Burns effect is enough for 99% of users, and what you want is a specialty item (that's easily made in Motion).
Try this:
http://fcpxtemplates.com/free_stuff/sc_simpleCamera.zip
It's just a "camera" object with the Position parameter published. It is a single click keyframe setup (X,Y and Z) if you keyframe "Position" [dial down the disclosure triangle to do XYZ at once on the Position "line"].
This was left "raw" as part of the design. Design benefits include using this effect as a magnifier callout by using a Shape Mask and being able to position the camera to exactly fill the magnifier area. Another design benefit is that the keyframes can be Smooth (default) or Linear [use the Video Animation pane and right click on keyframes to set which.] Using the Position Z parameter (on a camera) is far superior to using Scale.
The "downside" : Camera moves are backwards from what you would expect [opposite of Transform parameters]. Zoom In means going into negative Z [camera moves towards subject]. Moving right and/or up is going in the negative direction parameter-wise. So when you use this, just keep thinking how "you're looking through the camera" and what you're seeing is how the lens "sees" the scene. As the Camera moves right - the image moves left; etc.
You can keyframe as many moves on a clip as you like; start and finish however you like; etc.
I tried making this with onscreen controls... but I think the trade-off [loss of smooth/linear keyframe choice] was worse. It's more like Ken Burns with the interpolation option.
