Based upon the above, one might therefore conclude that a moderate democracy in which administrative power is not allowed become permanently established is the favourable option.
I won't deny that, but I think that it is also important to stress that the executive and legislature should be controlled by the same party (though, only a slight majority of the legislature) while the judiciary controlled by the other.
If the parties are different then it can lead to deadlocks on important issues, which can cause more problems to arise. I also think that which party is the one in control of the branches needs to switch occasionally. 10-15 years ago I would say a Democrat controlled executive and legislature with a Republican controlled judiciary would have been better, not I feel the opposite.
There is a sort of pendulum that swings back and forth, with the left ending up going too far before the culture shifts to one where the right is better. Eventually the right will go too far and it shifts to where the left is better. Whichever side it has shifted too far on is the one that should not be in control of the executive and legislature. It is when the pendulum doesn't start swinging back that the chance of civil war increases and the country collapses.
Never should a party get too much power established, but so too should it not be at a deadlock when it comes to the importance of responding to issues (which is ultimately the legislature and executive working together). Enough power of the minority party to prevent chaos, not enough to cause deadlocks.
That balance is what I find important.