The animation timeline in photoshop is complete amateur hour garbage. In flash you can tween a cycled animation as an object, scaling across the stage in just a few clicks, then easily double click the object to enter its timeline to adjust the animation. SUPER simple.
Photoshop requires countless points, clicks, menu scrolls, and scrubs to perform just basic scales and tweens. The difference between Flash's animation setup and Photoshops is the difference between cutting your lawn with a riding mower, vs a shaving razor without the handle. Please update this aspect of photoshop to a professional level. Printing 'professional' on the box doesn't make it a professional level product.