Question for those who may have some technical insight. Why do you think Apple went this route if in fact these are the byproducts (below)? Is it merely for the convenience of interoperability between Motion and FCP X? I have to admit that generators I make with Motion for FCP X can be ridiculously slow to render.
Issues (copied from wiki site):
Slower to load and render than native plug-ins, presumably due to the extra work required to load and render a Motion project.
Poorer output quality than it is generally possible with a native plug-in. Footage may be scaled to full-frame, cropped, etc. thereby introducing filtering artifacts. Results vary according to the version of Final Cut Pro used and the snapshots included by the Motion Template.
Templates cannot be deployed or installed easily. Developers and end-users have additional responsibilities to ensure that visual effects can be found and loaded by Final Cut Pro X.
Templates are inherently open. The architecture contains no provision which prevents end-users from editing and/or redistributing your templates.
No parameter grouping. The specification contains no official method for grouping parameters together in groups, thus making it extremely hard for users to learn and use complex products where a large number of parameters is unavoidable.