You will need that rule, nothing has changed with the requirement of using
mod_rewrite to remove the index.php portion of your URL for your site installation. You still need to direct all non-file/directory URLs to that index.php file as well. Please review the docs:
If you are looking to refactor your
.htaccess file, I would start with the docs recommend set of rules, and add back any custom rules you have one by one, and eliminate relics from that file.
Without seeing what is actually in your
.htaccess file, and without knowing your server setup, it's hard to recommend a blanket statement to remove any specific rules. But like I said, if you want to refactor, start with the docs recommended set of rules and add back in what you find you need.