I believe that there is a more appealing side to it then what you have described. You have provided much better comments than the others, but you still convey some amount of distrust of the possibility, and although, you do not accuse me of being a tyrannical dictator, as so many other distrustful commentators have, you cannot avoid describing such anecdotes.
How does a "scientist" who has generated a just system describe it to the populous that is so enamored with the erroneous subsisting system???
"populace"
I would start by choosing the proper medium and venue. For describing an entirely new system of government, the only fitting media would be a university thesis, a book, a manuscript, or at the very least a lengthy whitepaper. The reason being that the document would have to establish to the satisfaction of the learned reader that the author
i) had exhaustively researched existing systems of government, philosophies of government, and proposals for new systems of government, ranging from the archaic to the contemporary,
ii) could present a cogent and defensible case for why a given problem in society (or collection of problems) is indeed a problem that needs to be solved,
iii) could present a cogent and thorough (to the utmost) description of a novel system of government,
iv) could argue logically and persuasively in defense of the new system, in particular to establish its novelty, its unique promise as a solution to the social problem(s) identified, its feasibility, and the full corpus of evidence favourable to its defense,
v) could capably address (at the very least) the most preliminary and obvious criticisms of the new system,
vi) had provided a clear proposal on how the new system could be implemented and evaluated--preferably at modest scale--as well as a clear idea of how success versus failure would be measured, and
vii) had supplemented points (i)-(vi) with so much relevant knowledge from existing literature (including ideas, data, examples, laws, etc.) that it left no doubt he (the author) had invested years of intense work into conceiving, fashioning, refining, and testing a truly novel, realistic, necessary, and well-conceived alternative system of government.
Even so, such an author shouldn't expect his work to have widespread recognition. If it did receive recognition, he should expect a lifetime of intense criticism. In the fantastically unlikely circumstances that it received recognition, endured criticism, and prevailed over hundreds of competing proposals, if it's a truly revolutionary (i.e. radical) redesign of society, the author shouldn't expect it to see it implemented in the real world unless/until some cataclysmic event shook the foundations of the established government and prompted the search for a superior alternative. At this point, the author's original thesis would be regarded as more of a manifesto, similar to selected writings of Plato, Locke, Descartes, Hegel, Kant, Nietzsche, Marx, and even demagogues like Hitler and Mao, among countless others. It would likely happen posthumously.
Personally, having observed the violent resistance to proposals as modest as tweaks to voting procedures (e.g. photo identification, e-voting, "quadratic voting"), trying to sell the wary public on an entirely new system of government is not something I'd ever attempt in the 21st Century.
On a message board, I'd limit myself to discussing specific, tightly-proscribed proposals already in existence that might have a snowball's chance in Hell of actually being implemented somewhere in our lifetimes. For example, a poll asking "What do you think about quadratic voting?", along with a description and references to pro/con articles for sake of the 99.9% of readers who have no blessed idea what "quadratic voting" is or why anyone should care.
