I’m not convinced that the task switcher needs to exist. Since apps in the task switcher aren’t really running, the task switcher isn’t so much a task switcher as it is a list of recently used apps The task switcher lets you switch back and forth between apps one handed using your thumb. I think that's part of the rationale for it. Also, the Least Recently Used algorithm will dynamically make a short list of the actu…
One handed? So no pinch-to-switch-apps gesture? (it seems odd to point out one handed operation of an iPhone feature when so much of the reason people say it is superior are the things that require two hands to operate).
In this case, the real alternative to the task switcher is flicking through multiple pages of apps, which surely is more difficult than a simple row of recently used apps. It's hard to imagine a pinching gesture that would be usable here, without interfering with the current app.