Constitutional Reconstruction needn't be needed!

In  an OLLI class I'm taking at University of California-Davis (see reference to class elsewhere), we recently took up the reasons for revising or chucking an "active" constitution, i.e., already in use in some particular country.

The usual reason proffered is to resolve a Constitutional Crisis.  That is to say, the country is in such dire straights that society as a whole is at risk of falling into political chaos.  I take it (since I was there) that Russia in the late 1980s took to formulating a new constitution for this reason.  

But now, there are good reasons to come up with a brand-new constitution for 'positive and beneficial' effects upon the society. Both Catalonia of Spain and Scotland of the UK envision an independence state within some confederation of independent states, such as exists in the Russian Federation.  As independents, they can have their own methods of doing things.