My hope is that there is a forum for all the races and that, in the end, the races that were on top either topple or are at least given a serious dose of "da f'k u bring 2 the table brah?"
Mince it however you want - the old Council was run militarily. The Salarians, Humans, Turians and Asari had the greatest military presence in space. They bullied their way to dominance... and the humans underscored the gross inequality of the Milky Way Council by leapfrogging species that had been part of the Council for hundreds of years.
Sustaining a military presence of ANY sort at this point would be laughable and inefficient. A police force? Yes, of course. But a military replete with small fighter vessels? A gross waste of resources in a suicidal situations reliant on one factor alone. Sustainability.
- The Quarians know sustainable fleets. They would have been key in designing the Ark.
- The Volus know economy and ran the frigg'n galactic market. They would have funded the Ark project.
As for the Hanar and Elcor... I'm not exactly sure if they could bring anything unique to the table.
- The Salarians bring science true, but aside from biological genocide to compensate for their gross lack of biological understanding when uplifting species... I don't see how they excel in it. You would simply carry your science in databases... not scientists. And scientific advancement would cost WAY too much in resources for a survival trip. Scientific study is a luxury. (Note: There is a HUGE difference between how ancient man learned things... and the ponderous, cost heavy scientific method)
- The Turians had exactly what they don't need right now. They were space police, but anyone can be space police. Their fleet was a military power. They don't need that. They can't blast hunger, disease or morale with lasers and that's what these people should be fighting.
Militarily - you would probably make this trip with all relevant blueprints and schematics for developing a future military once colonization has been established. It is the most cost effective way of making the journey as refugees.
- The Asari bring... what.. the color blue? Hedonism? It seems the only things they're good at. Their biotic knowledge could, like all science, be relegated to a database and used once they discover if the Andromeda galaxy has Eezo.
I think Bioware will tell a generic story of how an absurdly large ship filled with an untenable population of varied species made a quick wormhole jump through with everything in tact... because it's an easier story than hardship and frontier-life. I hope it's different - but I don't think it will be.
As for the protagonist... he should be an explorer in the sense that all explorers have been. A rugged survivalist cut from the conveniences of civilization and set out to be a herald in a dangerous, unfriendly environment.
Having said that... I'd actually like the Ark itself to show up at the END of ME:A and have you and your crew ahead of the Ark and alone in the great emptiness of the Andromeda fringe.
Yes, the main protagonist should have agency within the microcosm of their story... but the greater story should NOT be in their hands (Example: Cassandra really should have officially run the Inquisition with the Inquisitor being just a specialist with a team.. not unlike the Chargers)