Not in the general case, no. But one of the major uses for rsync in synchronizing mirrors, and it could very much be a replacement for rsync in that particular niche.
Better rsync support is actually in the works (though probably still a ~quarter out to land end to end in go-ipfs). The two main components are improving ipfs "mount" support, and adding metadata support into unixfs so we can only update modified files. See details here: https://github.com/ipfs/team-mgmt/blob/master/OKR/PACKAGE-MA... -- mount currently has IPNS read support but write support needs an owner to get it over the finish line and unixfsv1.5 (with metadata) should be landing in js-ipfs later this week!
Ah, yes, you mean pinning a specific set, you're right. Unfortunately I've found that the way the daemon does pinning currently doesn't lend itself to that use case (a single unavailable file will stall the pin for hours).
