Many principles in computer architecture were discovered loooong ago. Pipelining, multi-core cpu's, virtual memory, various types of caching, etc etc. It's just that today's tech squeezes orders of magnitude more logic into a mm^2. So the scale of what's considered a small or big project has changed.

Obviously that requires a more rigorous approach. So I'd expect courses in this field to put more emphasis on testing & validation methods (and tools to do that).

> ARM has exploded onto he scene

ARM is mature tech now. I'd say most excitement is around RISC-V these days. Well that and GPUs, AI accelerators, FPGAs, manycore cpus, photonics, quantum computing, ...