I honestly can't tell if you're trolling. In what world is it better to instead give all the say to one person? Especially a person selected solely by their prowess for violence (or in leading others to violence)?
If that one person is wise, virtuous, and really prioritizes the people's best interest, and is willing and capable of delegating and seeking advice from people who understand various domains better than them, and is a good enough judge to choose good people for such delegation and advice, then it could be at least much more efficient than a democracy or republic. Decisions could be made much faster. And such a leader could very well be better at making decisions that are better in the long term, even if they aren't in the short term.
However, how do you find and appoint such a leader? And even if you somehow get such a leader, how do you ensure their successor is just as good? Selecting a leader based on military prowess definitely won't get you such a leader though.
First, that's a big if. Second, it's the old pipe-dream that there are decisions that are on "best interest" for everybody, that can just be based on "domain knowledge", and not competing interests to be heard and balanced.
>Decisions could be made much faster.
That persons decisions. Not the ones people want. Basically you're described an infantilized population and a parent/nanny that knows what's best for them.
Productivity requires decentralized decision-making. The more centralized the power structure is, the lower the overall productivity of the subject population.