the reason we hear about Goldmoon is because she did it first and brought the gods back. If someone else did it six months before, then maybe we should have heard about that before as well.
Whether you consider that a minor thing or not is up to you. It certainly is a change.
The reason we hear about Goldmoon is because the books/modules that were written in the 80's talked about her. In a world without Internet or any means of communication, where travel is very difficult and dangerous, and you have some serious upheavals in the world very shortly, not hearing about something that happened isn't unreasonable at all.
Again, this only applies IF your group happens to have a cleric. Y'know, one of those classes that are not all that commonly played?
Meh, people will kick at a football game. This whole discussion started up because of claims that WotC was "massively changing" lore in recent years. Yet, funnily enough, they actually aren't. If SotDQ suddenly added new gods, THAT would be a massive change to the lore. 2e adding in the freaking Great Wheel to Dragonlance was a massive change to the lore (previously, there were no devils in DL). Having a couple of clerics pop up at around the same time as Goldmoon? Yeah, that's not a big deal.
Spelljammer still has flying ship, flying with SPelljammer helms, traveling the existing realms of D&D. A version of Spelljammer that is a thousand times more successful than the original. A new version that is VERY light on lore. As in downright emaciated. Which means that 99% of the existing lore from the old setting can be used without any changes. I know because I do it. I can go to places like the Spelljammer wiki or the old setting guides, and port them in verbatim into Spelljammer with nary a ripple.
The issue isn't that there are changes. I would certainly hope there will be changes. It's the claim that "when they started overtly messing with the setting lore". Yet, for the most part, setting lore hasn't been particularly touched at all. That's been the constant refrain all through the 5e era that WotC doesn't do lore. That their books/setting books/adventures, don't do lore. But, apparently, "recently" they've been massively changing lore?

I'm not even sure how that's supposed to work.