If arc could seamlessly access PLT scheme's libraries that would be a good start. I know from first hand experience that there are a number of ways to access PLT scheme from arkani and arc. But, there are two big issues. First there are type differences between fundamental types (lists gah). This means there can be a lot of work to convert between PLT scheme and arc, not impossible but time consuming. Secondly, there is no nice way to pull in a PLT library and just use it in arc. Of course this could be implemented - it's just not there yet.
There are two choices I see going forward immediately. Arc and the arc community starts implementing their own libraries or we find a way to use PLT scheme's libraries (ok maybe sbcl if you are using arkani).
I know there is additional information somewhere in the forum on type differences when coercing data between scheme and arc - specifically '() nil (list) aren't equivalent. Worse come to worse - see the source.
