Romantic plotlines for Hawke predate her assumption of the title of Champion and in most cases flirts can start even before the Deep Roads expedition. Hawke is never the head of an organization and is never described as a professional anything; her companions aren't under her orders but are instead basically just her closest friends.
Which makes DA2 maybe the only BioWare game since KotOR to have companion romances without that particular super-squick factor.
As for everything else, well, you already know I agree with you about almost all of it. 
In some respects I think DA2 has been the best Bioware game to date in terms of not only romance variations, but in how the structure of the game favored potential romance types.
To start, I for one loved the rivalry and rivalmance system, which took five characters and gave them two different character and relationship arcs, including (and especially) an option for if you disagreed on somethings yet still liked the characters. Romance options were no longer 'thous shalt agree with the NPC or never progress', but instead broaded more. You might not like all the relationship types... but you had more flexibility in how to engage a character.
Second, the time skips made a narrative of progression much more credible and convincing. Rather than 'brought together in a brief time of crisis,' to me the DA2 romances and character friendships felt more like 'matured over time.' This also helped with that point about being able to start relationships and such before your rise to power.
But thirdly, having the entire game and story set in a single geographic area would have made justifying NPC romances so easy. One of the harder aspects of non-companion romances in many Bioware stories is the question of 'where does the NPC live?' When the party is always traveling and on the move, either the NPC has to be tagging along for some reason (a crewmember on Shepard's ship), or at a centralized position the party returns to with some frequency (advisors at the Keep). But Kirkwall is one giant centralized location, and from the start Hawke has reason to go to all of the major districts, which meant that the common question of how to justify meeting and being accessible is resolved. A low class LI in lowtown, or a noble in hightown, either would have been perfectly accessible and could have been rationalized and incorporated into supporting stories.