Could we apply the uncertainty principle to any quasi-stable system like the Universe ?

This is a moot question.

We can't "freeze" energy transfer and we can't "freeze" time.

When we observe a system undergoing entropic changes we actually increase the entropy of the system by the energy involved in perceiving the change, the same applies to time. i.e. moving clocks slow down time (resistance to the flow of time increases) and "time entropy" increases.

 

Could then the Uncertainty principle that fits the micro and nano world have larger implications?

 

I wonder.

I think maybe you should look at the mathematical engrossing of the uncertainty principle

 

[latex]\sigma_x \sigma_p \geq \frac{\hbar}{2}[/latex]

 

That is two standard deviations multiplied must be greater than h_bar over two - look up the value of h_bar. The "macro-world" as you nicely put it has far greater implicit uncertainty than would be required to reach this level. The formulation for energy time is similar - a bit more complex - but again when looked at for a sizeable number of test objects the levels of accuracy will be way way outside the levels of the uncertainty principle.

 

Anyone combination of the tiny world (ie that which the uncertainty principle applies to) and the macro-world is fraught with difficulty - because to move from one to the other one is forced to make assumptions, estimations, and aggregations all of which will put your errors and uncertainties way past hbar over two.