Someone uploads "serde2"? that's blocked forever. Someone uploads a typo version of a popular package? Too bad for you, learn how to type.
the github connection
If you want to contribute to crates.io you're bound to github. No gitlab, codeberg, gitee, sourcehut, etc.
Not sure if there are any other problems, but those two seem like the biggest things and #1 is AFAIK not something they ever want to change + it would be difficult to as one would need a migration strategy.
Yep, so did I. Had to come up with a long-version of my package name in order to upload it. Not much of a problem for me as nobody uses the package but me - at the moment. If that ever changes, it'll be confusing.