I am happy with the fact that 'for', 'grep' etc evaluate their args in lvalue context and thus autovivify, and I don't wish it to change. I find that this behaviour makes the rules for autovivification logically simple(r) and consistent.
I am unhappy with the deferring mechanism in hash lookups when used as an arg to a function call. It's a tricksy special-case behaviour and is hard to explain (above, I had to start talking about PVLVs and showing the output of Devel::Peek). It adds performance + memory overhead for such function calls, and is too clever for its own good. But I'm not proposing that it be be changed, since it was intentional behaviour added over 20 years ago.