The OP was asking for disadvantages of Perl, and I was giving him a common view. An easy thing is only complicated to achieve, which violates a mantra of Perl.
In fact this criticism is so widespread that Larry already changed this design in Perl 6 (almost a decade ago): @ and % default to references and the comma operator is changed.
IMHO that will (sadly) also be the biggest source of confusion for migrating to Perl6.
To be clear: I like flattened list, just shouldn't be the default.
<code> <a> <b> <big> <blockquote> <br /> <dd> <dl> <dt> <em> <font> <h1> <h2> <h3> <h4> <h5> <h6> <hr /> <i> <li> <nbsp> <ol> <p> <small> <strike> <strong> <sub> <sup> <table> <td> <th> <tr> <tt> <u> <ul>