Memory protection on the Amiga is a bit of a topic really.
ExecSG so far has what we refer to as "weak" memory protection, that is, it protects unallocated areas, code, kernel memory, stack etc. I think you will find that the memory system is one of the most worked-on places in OS 4, we already have implemented quite an amount of feature, like said memory protection. There will be more technical details RSN.
About OS 5, I don't know. I have hope that our involvement ends somewhere in 4.x, although Operating Systems was one of the topics I studied at university, I really want to go back to what I really want to do - programming my own games.
