Yes. I experimented with the go IPFS client but stopped using it after noticing that even a fairly small share was burning up 75% of a CPU core all of the time.
Our initial research indicates the thing that needs the most attention isn't the DHT (a commonly-cited source of slowness), but the data transfer protocol: bitswap. We plan to tackle that in the coming months.
Do i think Rust could have a better, more generic library with code that is far more concise than Go? Yes.. but that's not likely the cause for ipfs-go's issues.
I can definitely see a chance for a rewrite producing better code though. As much as i'd love to give Rust that victory, i just can't imagine Rust is _that_ big of contributor in this specific case.
We are going to experiment with such improvements, and try to work with protocol labs to standardise them if/when we come up with a good solution.