The big problem with any slider is that it creates a blank space at the top of the website, since flash and JS are invisible to search engines.
Goofle likes some useful information to show when the page loads, and if you have a big slider, the only content you are telling Goofle that maters is the navigation.
When you remove the slider,or reduce its size, more information of value to the reader rises toward the top of the page.
Goofle does something called "first priority" when it comes to all SEO. Whatever comes first will be considered most important to Goofle.
Words near the top of a page will have more influence than the words in the footer. Words at the beginning of a paragraph, title, or description will have more meaning than words later. The first link on a webpage is the most powerful, the first paragraph has more influence on the page, the first sentence is the most important in the paragraph, and so on. Even the first links you get to your site are more powerful than newer links, and grow more so as time passes.
That is how you optimize your page content. Put things where Goofle likes them.
When you put a big blank space (a slider) at the top of the page you are missing out on the third most important piece of SEO real estate on the page.
