In a normal RPG where you are following the Story and mobs don't respawn, you wouldn't even think about ennemies scaling.
This is the heart of the matter. The open world is the root cause to so many of the problems plaguing DA:I, I really wish Bioware had stuck with what they're good at and not jumped on the Skyrim hype train.
The level scaling of DA:O was pretty much invisible. You could handwave away any consistency issues because you changed zones frequently enough to simply explain that the carta dwarves in Orzammar were stronger than the werewolves in the Brecilian Forest (in fact, tbh I never thought about it before reading through this thread. It felt natural to me). It would have been very visible and TERRIBLE if you had had the option to revisit e.g. the Cousland castle and suddenly found the Dire Rats to have similar hitpoints and damage values as the faction boss you killed 2 levels ago.
I don't know what the great appeal of the "open world" is tbh. I'd much rather have a captivating, well-crafted and cohesive story through a linear sequence of areas (which is not linear storytelling btw.), thereby eliminating level-up or storytelling issues, than a large "open world" that experiences problems like the ones we're just discussing.
Edit/PS: I just realised that DA:O could have exactly the same issues, I simply never ran into them because I always completed the zones I'd started, I didn't jump between zones while one remained unfinished. *shrugs* The point remains, level scaling is horrible if it leads to situations as described above (rat --> dire rat = faction boss).