You haven't played it either, and there isn't any indication that there will be anything right with the feature. When has a feature that hands over player units to AI control ever worked out well? How about automatic rebel suppression, does anyone still actually use that? What about the "feature" that hands over your country to AI control if your connection drops in a multiplayer game? (I don't play MP so I've never had to deal with this personally—not even sure if it's still in the game, in fact—but I've never heard anything good about it.)
Features like the macro-builder, that make player micromanagement easier, are great. Features that attempt to sidestep the micromanagement completely... well, with those Paradox tends to put its foot in its mouth.
The macro builder for unit templates is an example of something done right IMO (autonomy and a few others could be improved, but aren't harmful to use like fleet transport), I don't see how that one can be improved, in contrast with "automatic fleet transport" which has done everything from blocking legit land movements to selecting fleets from across the world when an eligible fleet nearby would suffice to crashing the game if attempted under some circumstances (especially lots of single transport units).
I suspect we'll see something in between with "add to this stack", since it'll probably just take the closest eligible province that's not building something, build it, and have it chase/merge that stack. In contrast with early fleet transport, at least, it's unlikely that the game will pop-up prompt you to do this in the middle of a war in nonsensical fashion. If it works well, great, but at least it won't actively hinder gameplay if you ignore it so that's a plus.
Removing buildings from the ledger was a pretty big QoL too unfortunately.
The only time I use much auto rebel suppression is when the micro of it all wears on me too much, or in the new world because the CN babysitting is tiresome compared to self-micro and the benefit of self micro there is marginal. Auto suppression in pan-Asian type empires is just awful...it functions best when you leave stacks at the most centralized location you can find, which necessarily means that you'll leave lots of provinces occupied a while but eventually it gets too hard to care.