First of all, variety does not solve problems. You don't make an ending good or well written by offering a wide variety of them. The idea that offering a wide variety of endings is automatically good writing and game design that makes everyone happy because 'you choose' the ending is very wrong and frankly just leads to incompetence on behalf of the writers.
Secondly, you shouldn't really 'want' one conclusion or another when you have no idea of the thematic content of the story.
Neither does BioWare. BioWare cannot control how we consume their content, so they shouldn't sacrifice other parts of the game in order to do it. Because it won't work.
It doesn't even work with books or movies, so it's not going to work with an RPG.
As such, the themes are not theirs to decide. The themes (which don't actually exist within the game) are ours to decide. I can play DAO multiple times and see different themes emerge each time.
Which is why
themes don't matter. Much like the writers' intent, they're not actually part of the game's content. We invent them ourselves. Any themes you perceive are your own creation. They're nothing more than headcanon. And like other headcanon, they don't matter outside your head. They might be really important inside your head, but that doesn't make them real outside your mind or that specific playthrough.