For some reason the built-in Timelines and Tween behavior, while being great features, have a much worse performance than 3rd party LiteTween behavior executing the same task. In this test - changing only the angle property for multiple instances.
Here's a live demo press 1/2/3/4/5 to turn on different animation modes and R to restart layout and reset animations.
Here's performance overview:
LiteTween - best performance; Timer + Set Angle - second best; TimeLines (Relative) - third; interestingly, TimeLines (Absolute) and Tween both have the same performance, worse than TimeLines (Relative).
This is an extreme example, of course, with 500 characters, each consisting of 13 body parts (which is still not that large a number for something like an RTS). But on a mobile the threshold is much lower - timelines and tween struggle with 100 characters, and that's the animation alone and only with one property, so with some game logics and collision checks it would be even worse.
Here's the demo c3p