Do you think that the App Switcher preview cards in iOS are too small? If so, then FullSwitch, a release that brings a full screen App Switcher to iOS 8, might be just the tweak to scratch your itch.
Along with the full screen App Switcher, FullSwitch brings privacy mode, customizable multitasking indicators, and a special Home screen menu to iOS 8. We've taken FullSwitch for a walkthrough on video, so check it out.