All of these are good points, but I wonder if it’s really a fair comparison. If you wanted to really look at something that’s hero’s-journey based but that has a comparable level of sophistication to Dramatica, I’d think you really need to look at something like John Truby’s Anatomy of Story. (It’s been a while since I read it, so this is from memory …)
In Truby’s case, some of your critiques still hold true (no concept of Steadfast characters or separating MC from Protagonist), while others don’t and/or are more complicated. Truby is all about “inner and outer journey”, and absolutely addresses theme. Some of his thoughts on archetypes would map to Dramatica’s concepts (but not all). As for the influence character, some of that shows up in his concept of Antagonist and/or Ally.
The big negative of Truby is that when you dig in it’s just not as precise as Dramatica. I actually found it more complicated to understand and apply.
On the other hand, while Dramatica-types might find it limiting, it’s possible there’s a certain power and freedom in having an a la carte approach where you can suddenly realize “oh! that character should be a false ally” without getting lost in IC throughlines and handoffs or wondering if that bit you wrote really counts as MC or if its RS. For a lot of people, storytelling metaphors like “ally” might be more user friendly than the clinically precise “influence character”.
I also think he has some useful non-structural storytelling ideas (which Dramatica doesn’t deal with at all). Matt Bird, McKee and others fall into this category as well.