Is this the official standpoint regarding ARexx, that it is obsolete? If that is the case, what is it replaced with? Python?Arexx support will not be added [...] Arexx is basically obsolete and parts of it are still in 68K assembly language
Because ARexx is, imho, one of AmigaOS's more important features. I believe that ARexx is one reason why AmigaOS has aged so gracefully as I think it has. And I don't think it is merely due to the direct effect of new and old programs being able to talk to each other, but also much in how Amiga programs are developed, given a standardized OS supported way of exporting functionality, actually influencing how programs are designed.
Furthermore, I don't see how it being 68k has anything to do with it being obsolete given that the OS is shipped with 68k support builtin. In a (the) future where time and resources are given, it might even be feasible to rewrite the 68k ARexx parts.