I still don't understand this. If you are big enough then you get Amazon to make an official sdk, if you aren't then what exactly are you looking for?
The official aws cli used to talk to the soap interface and used regex instead of actually doing correct error handling and that was used by so many tools. Even though it used to break horrible.
It's quite a niche you are talking about, not big enough to debug open source code but still big enough to require SLA for SDK and not being able to talk Amazon into creating it. It's generated code, it's not rocket science.
What I have experienced is that software licence, where you are sending data to, where you are hosting it and having access to audit the code has usually been a bigger concern.
But then again big organisations often have really specific concerns. So I'm not doubting your statement it's just that I have never heard it before.
What are you talking about, there has been a AWS client forever and I've never had a problem. It's not something you really need an official sdk for they are anyway often just reference because you might want different performance characteristics.
I've usually not seen more than 3 or so official SDK for most services and there are a lot more programming languages than that. For example Microsoft's Graph API doesn't have an official Ruby client, they have one that sort of works.