You are right to point out that in my comment I talk about bash in terms of a language rather than just a shell; but I did have its shell-nature in mind while writing it, and in fact your example is exactly what I meant when I said that python is not good enough unix glue... there's a certain level of script complexity where python starts making more sense than bash, but because the ergonomics of calling other programs (unix glue!) or building pipelines are pretty poor, that threshold is pretty high.
Some of bash syntax makes perfect sense in the context of a shell-but-also-scripting-language. Some of it makes perfect sense in the context of "everything is a string", which I think is an absolutely great abstraction---for example, unset variables being equivalent to empty strings. Other parts are just jargony, and might make the life of a few experienced shell-slingers slightly easier, while complicating many users' interactions with the shell.
I suppose part of my point is that succintness here comes at the cost of readability. A shell could very well be _slightly_ more verbose than bash (say, requiring assignment operators to have two sides, so `foo=''` instead of `foo=`), still be plenty succint as a shell, but being slightly more explicit and readable in a scripting context. `foo=''` is only _two_ characters longer than `foo=`, and is already-implemented behavior. But the `foo=` syntax has certainly confused generations of unix users... that's just not a good tradeoff imo. I feel pretty comfortable calling this lack of foresight, or suboptimal design; that's not bashing (!) the language or its creators, rather, merely noting that we can do better.
And if you don't think so... check out fish shell! It's a beloved and successful shell, and they forgo the use of = entirely (instead, you have to `set foo bar`, which is more verbose and a lot more explicit!)
Edit: fish does allow `foo=bar echo $foo` to override variables, so they actually manage to keep bash ergonomics while avoiding mistakes while scripting.