Alright, so I just wrote out a mini-essay in the other thread about why I don't like this change lmao. I'll repost it here:
Let me go into detail on why I like the unpatched line more. Obviously, this is all subjective, but I like script analysis goddamit!
Aerith's line here is engaging in a bit of poetry. There is no "steel sky", there's a big fookin' metal plate above the slums of Midgar. But, for most of her life, that's what she's known.
When she says "I miss it... the steel sky," that line encapsulates so much about Aerith, the ending, and probably the player's reaction to the game itself. It brings back Aerith's own motif of discomfort with the open sky, but it also incorporates the fact that the game ends with the players leaving Midgar, so bringing the "steel" into the equation helps bookend the game. It begins in Midgar, and it ends with a reference to the steel of Midgar as the characters leave.
On a metatextual level, the player themself (probably an OG fan of VII) has spent this whole game in Midgar under the assumption that the game is just an expanded remake, but the defeat of the Whispers leaving open the possibility of change in the narrative moving foward mirrors Aerith's own trepidation. We were in Midgar, and we mostly knew what was going to happen there, but now we're leaving it, and we don't know what's ahead. It's a metaphor for something new, similar to how the phrase "I don't think we're in Kansas anymore" isn't necessarily referring to Kansas when we use it in everyday parlance.
So, while "I miss it... the steel sky," may not exactly sound "natural" in a normal conversational way, it's a "natural" line to end the game on, because it bookends the game well, gives us some insight into Aerith and brings up her own feelings toward the sky, and likely mirror's the players' own trepidatious feelings as to where this series is going.
I personally don't think "The Sky... I hate it," works as well in English as the original line in that regard. Admittedly, I don't know how it plays in Japanese, so I can't speak to its context there.