[sesquipedalian]

I don't believe non-stack based APIs prevent the implementation of the features you just mentioned. You don't necessarily have to expose the underlying stack manipulation routines as your defacto API although it is easier to do so. My gripe with this technique is that it makes it much harder for the compiler to catch errors. Personally, I think it would be better to expose the API as helper functions that compose (and hide) the underlying stack routines.