Two clarifications.
First, to find the "old IGI," click on "All Record Collections" just under Browse by Location," then scroll down to the I's, where the IGI will be listed.
After you click on it, you can search either the contributed data or the extracted data separately.
Second, the old IGI data is included in the general search results. It is in with other results, listed as "[country], [record types], [range of years]", for example
England, Births and Christenings, 1538-1975
The new site is vastly more powerful than the old one--you just have to get used to using the various filters. There's an online class on the FamilySearch Learn tab that explains how to use it.