Abrams did the same thing with the Enterprise in his Star Trek films. While the Xwings and Falcon did, of course, take off and land, I don't recall them doing anything in the atmosphere other than moving from ground to space, or vice versa. If nothing else, you'd think the rebellion would have employed them in that capacity against the AT-ATs on Hoth. Certainly torpedoes that can destroy large bits of Death Star machinery should be able to obliterate the Imperial walkers.