I would certainly like to see better LLDB support for Rust. (That being said, I am not a maintainer, just a semi-regular contributor to LLVM / LLDB / lldb-dap. So take my word with a grain of salt).
A person called “walnut356” wrote an article where he tried to make sense of it would take to make Rust work natively with LLDB:
He actually is also on this forum - CC @Walnut356 
Yes, it is a known pain point that LLDB’s extensibility interfaces are not as good as they could be and there is agreement that it would be great to make new languages easier to add. See New Language Support for LLDB - Improving Extensibility for a recent discussion on that.
current state of debugging in Rust
I assume you are aware of @vadimcn’s CodeLLDB? Note that this is more than just a packaged lldb. It is lldb + extensions for debugging Rust.
- Current collaboration between the Rust core development team and the LLDB development team.
I think any upstream changes to simplify LLDB’s interfaces to make it simpler to add new languages will be gladly accepted.
When it comes to accepting Rust support in up-stream LLDB, see this previous thread: Rust support in LLDB, again. Back then @JDevlieghere wrote
I guess this statement still applies, but not sure. As already said - I am not a maintainer, others will have to make those calls 
Also besides the question of “accept Rust language upstream?”, the thread Rust support in LLDB, again might be worth a read. Contains a bit of background information on Rust-specific support already in LLDB today, in particular around Rust-specific support for DW_TAG_variant