Well, the value a monarchy can have, IMO, is in areas where the tribe is the highest social unit most of the people have faith in.
Since the nation belongs to the monarch as a whole, the tribal structure is an impediment to his natural urges to consolidate power. This will then ideally lead to efforts to replace tribal loyalty with national loyalty. Further, the petty nobility that tends to be the scourge of such societies will be converted or replaced by a bureacracy where merit plays at least some role.
This certainly happened in Europe, though the process was neither clean nor efficient. Look at the Spanish in the Netherlands or the power plays by the Hapsburgs in Germany for just how bloody a consolidating monarch can be.
That being said, at times I think the best thing we can do in regards to Africa now is install monarchies. The problems with such an endeavor would be legion but I see no other suggestions that have much merit.
As for the larger point, traditionally there were three forces in European politics (and to a lessor extent American);
Socialists/Communists - the predecessors of the modern Left
Conservatives - monarchists and predecessors of the European Right and *perhaps* RINOs
Liberals - the predecessors of American conservatives and libertarians.
I'd really love to know how liberal came to mean socialist. In European parlance, liberal still generally means conservative/libertarian thought I see the term "liberal-left" coming into use.
Though it could prove profitable in certain circumstances; Haile Selassie was certainly a better steward of Ethiopia than Mengistu Mariam, rest assured.
The only truly conservative-or "liberal" if you prefer-parties in Europe are the remnants of the Yavlinsky/Chubais parties; extant only in the Russian oligarchs who now vie for power with Vladimir Putin, and the Pim Fortuyn bloc in the Netherlands.
"If you can cut the people off from their history, then they can be easily persuaded." Karl Marx
"The revolution will be complete when the language is perfect"--George Orwell, 1984
FDR and the intellectuals of the 1930s are usually credited with pulling off that remarkable feat of legerdemain. They were uncomfortable calling themselves socialist given Norman Thomas' failure to capture to the American imagination with the term, and of course to call themselves communists was anathema. So in all the trendy periodicals and opinion pieces written by guys like John Dewey and Sidney Hook, they started to assign themselves the designator "liberal." Unfortunately it stuck, even though, as you say, it really doesn't apply.
A lot of the sophistry, nonsense and evil born in the 1930s, that roiling decade of hard economic times, is still with us today.