So, serious question.
Should the runner not be allowed to mess with the Corps score pile? Or is the specific flavor/context of Turntable that pisses you guys off?
Because If you answer no to the first question, Turntable (or at least a card like it mechanically) is where things naturally end up.
If anyones going to be disruptive enough to screw up/negate finished corporate projects, it's going to be the Anarchs.
So how do you balance the effect? Really there's been a bit of problem with swinginess around scored agendas because nothing can touch them. While there have been more narrow answer to specific cards (Clot for Astro for example), something that interacts with agendas more broadly makes sense.
Just making the corp forfeit the agenda is a bad idea for pacing/"is this actually fun" reasons. It also has to have a natural barrier - you don't want this sort of effect to trigger that often. On stealing another agenda seems reasonable - it means that the way the corp guards against this effect while playing is similar to what they already know/understand.
You want to limit the ability of this to really hammer the corp agenda point wise - the point/value of the effect is in disrupting powerful agenda text, not making things take forever.
This naturally leads to the swapping mechanic. If the two agendas have the same point value, then points aren't even effected. If the just stolen agenda is more valuable, then the runner has a tough decision, which is great.
Putting it on an ID makes it too reliable. Putting it on most cards makes the opportunity cost to low.
So it ends up as a console.
So, challenge. If this what the designers wanted/needed mechanically, what do you do?