Hi Rehana! Both the Glycerin GTS 20 and Ariel '20 can be great options for fallen arches and wide feet. The Ariel '20 may have a little more width and volume, and as such may accommodate fallen arches better. We recommend visiting a local running shop and having your gait and feet analyzed by a Fit Expert. They'll be able to recommend options accordingly. To find a shop near you, check out our Store Locator tool.
https://www.brooksrunning.com/en_us/store-locator