If implemented, this change would make a mockery of any claims that Perl 7 will just be "Perl 5 with different defaults", as well as any expectations that it could be used to run "clean" (by some definition) Perl 5 code without modification.
Looks like a valid objection. I agree. With certain formatting style it is possible. But do you understand the strict as the default will break a lot of old scripts too.
Per your critique, it probably should not be made as the default and implemented as pragma similar to warnings and strict. Let's call this pragma "softsemicolon"
What most people here do not understand is it can be implemented completely on lexical scanner level, not affecting syntax analyser.