"..just alter your expectations of destructive operators.."
Yeah, I agree with this. I weakly think (without evidence) that arc's destructive ops are more functional, and it encourages a better style to not constantly make assumptions about precisely which cons cells go where.
On the other hand, a set of 'alias-friendly' functions could coexist with the existing primitives.
Hmm, I wonder if the notion of boxes would help build alias-friendly operations.
