There’s no conceivable way you (or any other developer) would be able to create the sheer amount of diversity necessary to make each/most/many worlds feel unique and special. Worlds which feature non-Earth life are the biggest problem here; it would take an enormous amount of man-hours to create thousands/millions of alien biomes which didn’t all look similar. No Man’s Sky is an example of how not to do it.
Anyway, when the time comes to finally add atmospheric landings, don’t do every planet at once. Don’t even do every planet of a single TYPE at once, if that type has a lot of room for variety. Start small, take the time to do it right. When you add landing on Earth-like worlds, add a couple of specific ones first. Earth itself might be a good first pick. But try to avoid doing what No Man’s Sky did, because they took a vast galaxy (or galaxies) and made it seem tiny, repetitive, and meaningless.
Anyway, when the time comes to finally add atmospheric landings, don’t do every planet at once. Don’t even do every planet of a single TYPE at once, if that type has a lot of room for variety. Start small, take the time to do it right. When you add landing on Earth-like worlds, add a couple of specific ones first. Earth itself might be a good first pick. But try to avoid doing what No Man’s Sky did, because they took a vast galaxy (or galaxies) and made it seem tiny, repetitive, and meaningless.