"first, 20 years old people are under age in some countries. (...) It's logical to keep it open. "
I'm confused. You're saying 20 is under age, but then, you're saying to keep it open for any ages to vote - which would include children.
What's the alternative you propose? Are you saying children and non-Asgardians could vote too?
"20 is also an unusual unjustifiable age."
Well, actually in Canada, 18 years old is considered legal adulthood, and thus individual decision making is recognised as legal, starting at this age, by the system. Canadians can vote if they're 18 or older. I wanted to use 18 but I know that in some countries the adulthood age might be set higher. 20 seems like a good, round number. Most people I know of that age are able to contemplate political ideas.
"What people want, and that's logical too, is a logical, fair and future-ready set of laws. "
Which a Constitution will bring. The set of laws must be very specific, and have legal effect, otherwise you'll open the door to loopholes and abuse of power. You can't just write a law saying "there shall not be any abuse of power", it's too abstract of a concept. You need a Constitution to explain plainly what the leaders can and cannot do, and what will happen if they break the law.
Remember also that the Constitution can be amended. I don't think we can pretend to know what the future will be like, nor what will be good for the people 100 or 1,000 years from now. This is why Article 5 P 3 is there - it makes the Constitution editable. It's not static - whatever the future holds, modifications can be applied unto the Constitution so that it evolves accordingly to the need of the people.
"You confound peaceful with defenseless."
I'm not the one confounding things. As I keep on saying, I left the creation of a military legal in the Constitution in the first place. Defence forces are not prohibited in the Draft (what is prohibited, however, is a military turning against its people, or enrolling people as soldiers against their will).
"We should also don't forget that Asgardians are a collection of people with origins from existing and recognized nations. So we should understand Asgardia as a global nation from my point of view."
Good point. I share this point of view.
"What ever results as the constitution, magna carta or what ever we named it later: It should be representative, easy to read, easy to understand and exact but not prejudging."
I totally agree. Finding a perfect balance of all these qualities, however, is not an easy task.