With regards to efficiency, a "unique design" is of little direct consequence; we are always mapping from one very different language to another, since assembly bears ultimately little resemblance to Java or Ruby or Haskell.
A language can be a bad compile target but that has more to do with runtime restrictions. For example, it's hard to build command line tools that start quickly if you target the JVM. Compacting GC can make interop with other languages hard (since objects get moved around). But Rust doesn't come with abstractions or an execution model that are any more heavy weight than C++ (which is no way a bad language for implementing interpreters or compilers, and has even served as a compile target on occasion); in fact it is a more conservative extension of C than C++ is.
Rust does impose a burden that is kind of like saying, your compiler/interpreter has to pass Valgrind+Coverity; but this is perhaps more of a help than a hindrance -- and it doesn't limit the kind of language you can write.