You did again. Cleared the finished maps on standard. Please preserve them after future league's

Keep in mind having an Atlas reset every league means players who want a Standard reset (and there are some who want it) can have it so they can do a new Atlas strategy or whatever and they don't have to invest in unshaping orbs or that sort of thing.

And it's really, really easy to get back progress on the Atlas as others have mentioned. Get a legacy map of whatever tier you want to complete up to, roll it however you like for the completion bonus, then run it and kill the boss and you've unlocked every map up to that tier. I bought a Minotaur map, transmuted it and it rolled ele weakness, regaled and it rolled chain, then vaaled it and it unidentified. Ran it right after the servers were up and literally completed every single map on the Atlas except the other T16s. Easy peasy.

Running a map to get back wanted completion is much easier than having to go through the Atlas map by map and even uncompleting certain ones to redo it to your desired strategy.