In the process of progressing modernization and mobile capability, and clean up the frontend user interface, we've taken queues from popular social networking platforms on several placement options; in this case we opted to move the post sharing and report post options to a post management dropdown to the right of the post in a downward chevron (ultimately exactly like Facebook, Nextdoor, Twitter, etc) versus adding multiple new buttons which will skew the design and make it look more cluttered.
If you're unhappy with this behavior you're more than welcome to modify your own forums to add additional "buttons" to the template; but we will be continuing to modernize the software, and modifications to the base code are not officially supported.
To add a "Report" button to the button line you'll want to compare code from the v7.7.3 post_side.tpl, post_top.tpl, and post_gallery.tpl template files. This section of code is for the post buttons within the templates:
The "Notify Link" bits from v7.7.3 are as follows, and were just after the replylink button.
{if $postrow[post].notifylink}
<span class="post-buttons nw"><a href="{$postrow[post].notifylink}" rel="nofollow"><img src="{$config.BASE_URL}/images/{$style_array.general}/notify.gif" alt=""> {$lang.NOTIFY_MOD}</a></span>
{/if}
Simply add the code that you *liked* back, code going forward will continue to evolve and change over time, we will be looking at cleaning up templates rather than leaving them looking bloated.