"Thanks! This imbalance thing is GREAT!!!! I never believed that you could improve your movement that much in such a short time. When dancing the slowfox weave tonight I could almost double the way I moved without effort. I hope I can bother you once more...Tango (which is our worst dance)- when I try the same (imbalance) thing there the Tango will start running - as you do not have rise and fall there. "
Well, actually, Tango probably has the least use for imbalance of any of the dances, and a Weave is not necessarily the foxtrot action that makes the best use of it, since the actual weave part is not very dynamic, but sort of constant height constant speed. But let's look at what you might do.
In tango, you will somewhat uniquely be able to prepare your moving leg out ahead of your body, and to actually keep your body stable over the standing foot during a large portion of the time you are doing this. In other words, you don't project your body much in tango. You will still be briefly off balance just before you put your weight on your moving foot, but as the foot is already there to catch you it will be something you barely feel and should not really be noticeable to an observer.
In the foxtrot weave action - I'm thinking a series of side lead and outside partner walks on the ball of foot with the knee flexed - you aren't really changing anything from step to step. You would get a slight imbalance as you project your body into each step, especially as you would like to keep your body forward over your knees and not behind them. But still it's not a very dynamic action.
In contrast, let's look at where you would get large imbalance and benefit from it:
Lowering towards a heel lead - as you lower and project the standing knee with the body over it, you are off balance. If you kept your body stable over your standing foot, the dynamic of this action would be lost.
Swinging onto a foot - here again you have your weight off balance in the swing, however you may already have your moving foot out there ahead of you, though without weight. You are off balance as long as your weight is only on your standing foot, but if you put weight in your moving foot your balance would be instantly restored.