Get Back the Old Mission Control
With the new Mission Control in El Capitan, it no longer groups windows together depending on the app, which many users liked since it provided a better view as far as what you had open.
However, you can get the old Mission Control back by going into System Preferences and selecting Mission Control. From there, check the box next to Group windows by application.
It's an easy way to get the old Mission Control back without downgrading to OS X Yosemite.