Apple's logic for keyframe control

While I know many of us might be a bit frustrated with the limited control we have over keyframes in FCPX, I would like to understand what is the logic with what is currently implemented. Specifically, with keyframe interpolation options. Here is a breakdown of the default properties:

USER-DEFINABLE:

• Opacity with curves (Linear, Ease In, Ease Out, Ease Both/Smooth)
• Position (Linear, Smooth)
• Anchor (Linear, Smooth)
• First Motion Published Parameter with curves (Linear, Ease In, Ease Out, Ease Both/Smooth)

LINEAR ONLY:

• Scale
• Rotation
• Crop
• Trim
• 360 Orientation (Field of View) with Normal mapping

SMOOTH ONLY:

• Distort
• 360 Orientation (X,Y,Z)
• 360 Orientation (Field of View) with Tiny Planet mapping

I find it really odd that the only parameter with a visible curve is Opacity. The surprising exception to this is that if you use Motion templates, you’ll discover that the first (and only first) published compatible parameter (including the slider Rig) will also benefit from a curve and all the options that come with it. Position and Anchor are the only parameters with basic Linear/Smooth toggles.

The linear-only list is much more extended. Scale being included here obviously makes it very problematic when mixing other Smooth animation such as Position. Yes, you can try to use the Ken Burns effect as a workaround, but you are limited to working with thru-edits to control the animation. A simple zoom and hold is nearly impossible because you have to match the position/scale of the clip following the thru-edit (Ken Burns does not provide specific values).

And then there are Smooth-only parameters. Distort seems like the odd one out here, but who uses that anyway? More annoyingly, when working with 360 content, the Field of View property is Linear only when using Normal mapping and Smooth only when using the Tiny Planet mapping. And since all Orientation properties are Smooth only, you have no choice but to use Tiny Planet mapping (and its fisheye look) when working on any reframing projects.

So what gives? What is the logic for a developer to implement this mishmash of keyframe interpolation options, while not giving the user any meaningful way to control them? I am in awe of this program and all that it can accomplish, so it’s all the more surprising when inconsistencies like this exist.

I’m not looking for Motion-level control of keyframes with curves, because I understand that FCPX is an editing program first. My simple request would be to provide the functionality that already exists with Position and Anchor to ALL keyframable properties. I don’t think such consistency is unreasonable to expect from a pro application.

And yes, I’ve made this feature request to Apple.