Hi, I am new to freelancer.com, but am familiar with PHP and Wordpress plugins. I have created a custom (admittedly primitive) plugin and child theme, both for my own personal use.
I am interested in your article rating plugin project.
From my understanding, you need a plugin which allows your editors to use a set of sliders to rate an article just before they publish it.
The plugin will also display those sliders (along with another set of sliders) to visitors viewing those articles.
This second set of sliders will basically be an average rating based on what all visitors to this article have selected so far. Visitors will see the average rating first, and then can click a "Rate article" link/button to contribute their own ratings. Using cookies, we can ensure each visitor rates only once per article. We can also display how many visitors have rated the article so far.
The sliders themselves can likely be widgets, so that they can be flexibly placed anywhere in your Wordpress theme.
I am confident I can create this plugin for you, in a timely and professional manner.