I too think this limit on dwellers in the wasteland is a joke, and trying to collect them in waiting position was instantly crashing my game. Simply click on the wasteland as usual to check the progress of your dwellers in the wasteland and simply scroll through to the very end. I was able to scroll until I hit the dwellers that were waiting outside the vault. I was then able to collect that way and only that way. Please Bethesda fix this issue I have a lot of time spent on this game but now there really is no reason to continue playing

Thanks, Capo for the workaround on this! I thought I was going to have to wait until the next update to let my dwellers back in. I hope they take away the dweller exploration limit. If you can handle your vault maintenance without those folks it should be allowed as part of the game.

Otherwise there isn't much for maxed out players to do. Exploring for legendary items to collect was keeping my interest.