"deterministic [..] architecture"

Yes, important point and one of the fundamental design consideration.

Objective-Smalltalk uses the underlying ObjC runtime, so reference counting it is. No GC, unless you run it on Apple's deprecated GC or GNUStep with Boehm. Your choice.

The "<-" character pair is actually supported, Unicode left arrow would also be nice. As a matter of fact, assignment is not a built-in operator as with Smalltalk, but a family of dataflow connectors that includes constraints.

The right-arrow "->" is also supported for architectural connection, such as when connecting the IN and OUT ports of a flow-based system or up-/downstream composite scheme handlers:

   (ref:file:{env:HOME}/Sites -> (MPWCopyOnWriteScheme memoryCache) -> (MPWSchemeHttpServer serverOnPort:8081)) start:nil.

This creates a web-server with the "Sites" directory of your home directory, via an in-memory cache.