Yes, I've tested it before. It's great for retiming simple animation. But if a running character stops, first goes their legs, after that comes torso, then hands etc. - each with their own easings. Retiming this with one time track ignores these limbs' offsets since you treat it as one merged animation, this is basically Ae's time remapping on a precomp. I also tried assigning each limb to their own time track, putting time track keyframes exactly where original properties' keyframes are, and even though that way I was able to retime my character like I would in Ae, I can't easily edit their poses anymore, because now time track keyframes and original property keyframes don't match on the timeline anymore. So either way it is a tough workaround that in the end creates a complicated mess for something that can be easily done in Ae with initial property keyframes.
Your plug-in looks awesome. Great for triggering tons of things and feels intuitive to use. A speed graph plugins seems like a much simpler concept, basically a calculator that translates speed adjustments to actual property values. Animating something complex like characters with native keyframes gives best control, if only you could control those keyframes themselves more efficiently 😄
It redirected me to https://developers.maxon.net/, do you mean my best bet is to learn coding plugins myself with the guides given there? 😄 Well, sad to hear C++ isn't that widespread. Seems like python is more popular, should I ask this in python thread? Also, I love Cinema 4d, but that "open source blender" makes me jealous, easily found like three gigs on fiverr on writing addons for blender, for a reasonable price.