The greatest flaw of Liberalism, and I mean this in the traditional context of the term, in that the Republicans are Liberals too, is not the belief in "All men are created equal." That is a major flaw to be sure, in that it is farcical to even believe its true. The Greatest flaw of Liberalism is the belief that Power exists to bring about utopia. An utopia where everyone is happy, everyone is free, everyone gets what they want. That is not what power is for. Power exists to be used for the furtherment of those who wield it.
The purpose of morality and traditions is to inculcate in those who wield power a sense of duty and care to the nation and their subjects. Such that when Power is wielded, it is done for the benefit and advancement of both the wielder and his subjects. This is something traditional societies did. It is something Liberal societies do not. In fact, Liberal Societies are absolutely allergic to the idea that people need to be inculcated with the idea they are not an individual but a part of a great social structure in which greater power incurs greater responsibilities.
I agree with some of this, but "classical" (if that's what you meant by "traditional"?) Liberalism most certainly allows for, and sometimes assumes, "duty and care" by "those who wield power." Classical Liberalism is not devoid of morality and tradition; often-times, though, primary thinkers/ shapers of it assumed moral/ traditional/ cultural norms and simply didn't see much necessity of prescribing it through government.
In reality, "Classical Liberalism" has many strains of thought, fairly divergent on the role of state, import of economic theory, and general or personal humanitarianism/ decency/ morality. Most have a fairly hands-off view on legislated obligation, but not all Classical Liberals ignore it altogether. It's also worthwhile to situate some thinkers in their personal and socio-cultural locations, and what the common/ assumed expectations are. A man who personally values and feels obligation to others may argue for theoretically pure low interference in decisionmaking, but he may not fully extrapolate the impact of an absolutist strain of a society where there are no cultural traditions of general regard among men.
You said,
The Greatest flaw of Liberalism is the belief that Power exists to bring about utopia. An utopia where everyone is happy, everyone is free, everyone gets what they want. That is not what power is for. Power exists to be used for the furtherment of those who wield it.
and also, "[...] when Power is wielded, it is done for the benefit and advancement of both the wielder and his subjects." Not all Classical Liberals are utopianists. And a general, if not articulated, notion of
noblesse oblige was far more embedded in many Classical Liberal thinkers' assumptions than it sounds, because they largely spoke in theory-mode. Earlyish Classical Liberal philosophies, especially, of "leave people alone" incorporated certain assumptions about those with inborn or acquired power, the balance of human natur, and cultural (presumed universal, at least for all those who rated consideration) norms. Many of them believed that
most humans would make good - or at least not macro-level devastating - choices, that there were enough "good men" making "good" (positive) choices...choices within the thinkers' own and observed contexts. If they committed (thought-) "crimes," it was the belief that morality (and common) tradition would flourish without either church or state (their primary focus was state) setting and enforcing requirements, and that neither raw individualists nor immorality nor straight self-interest could critically wound society.
There is no "Classically Liberal Society" on Earth. And in much of the world, at least in the US and Europe, Classical Liberalism as a cohesive theory has been bifurcated and repackaged current-day into aspects of certain versions of what we generally consider conservatism and liberalism.
