I completely agree that this a giant PITA. But glad it's being considered to be part of toolchain. I would also suggest you reconsider the functionality of importing C headers directly. Yes, they won't be as nice as Odin bindings but they'll definitely give a nice stop gap. Just recently I had a project that uses WebGPU but couldn't generate Odin bindings automatically or find an existing one. So had to go with C++.
Another aspect is, many times I deal with proprietary APIs that have headers with all sorts of macros, bitfields and byte paddings. Having a direct C header import might also help with this case. Yes that API will still be ugly and less ergonomic but everything else would be nice. A bit like Futhark for Nim[0] or lcpp for LuaJIT[1] would really help to write more Odin.
Standard Library - I don't remember off the top of my head but I tried strconv procs a while ago to parse OBJ files and found that the floating point parsing to be slower than strtod. Maybe it's not the case anymore I'll give it a try again and open issues on Github for any feature requests.
Bitfields - In my line of work this is a must-have.
[0] - https://github.com/PMunch/futhark [1] - https://github.com/m-schmoock/lcpp