I've personally never had issues with the rain, so didn't follow the threads as closely. But I do recall Chris explicitly saying repeatedly that rain had nothing to do with the issue. But apparently every zone that HAD rain, had an issue. Iirc this was a big issue/started being an issue during the Sacrifice of the Vaal release?

For the rain issue I can at least understand the hesitation to get rid of them, they seemed like a part of the terrain of core areas of the game. An area of the game that would be explored and seen by many new players that GGG hoped to retain with their new expansion. I might also wildly guess that maybe it's difficult to get rid of the rain without doing major work to the areas that contain rain. And finally, I believe Chris stated that turning off the rain seemed to have no impact with the issues people were describing. Again, I didn't follow all that closely, so I could be off on these statements. (Plus, I'm apparently old now and so suck at remembering things I did read)

What I don't get about ground effects is that they don't have any of the same impacts as the above. Ground effects are an end-game feature (or otherwise a feature targeted at experienced player e.g. the 1m leagues and tempest) so their disappearance from the game wouldn't impact any newer players, not that there is a current large surge of new players with the challenge leagues down and an expansion not all that recent. Also, being a map mod (for the most part) they're already shown that "disabling" them is fairly easy, either remove or lower to 0 or .00000001 or whatever the chance to roll them on maps and they're essentially gone. They could still appear in Zana missions and Tempest Zana Mod or other some rarer instances, but this change would address most cases quite simply. And lastly, unlike the rain issue where GGG said they couldn't find a reason the rain was an issue/disabling the rain had any improvement on performance, GGG has already admitted that ground effects are causing performance issues.

Again, since I didn't follow that issue closely I could be slightly or widely off on many of the above, but I guess I'm saying I somewhat kind of understand that issue. I'm not looking for an absolute answer about ground effects, but I simply can't think of a reason as to why they're insistent on leaving them in the game when they admit they're an issue. I guess at this point I'm looking for even seemly weak arguments as to why they're left in the game.