You should probably start a new thread for this.

My number one guess of frustration would be (de)referencing rules with sigils.

(The deeper reason is the transition from Perl4 to 5 and trying to piggy back new features while retaining almost full compatibility)

Update

For instance take pushing to a AoHoA passed as reference $arr

Compare Perl

• push @{ $arr->[0]{key} }, "foo";

• arr[0]["key"].push("foo");