World Silent Expanse Quests Are A Joke, Qa Team Is Ignorant.

Kinda, it depends on the implementation:
If you're seeking to be able to commit each simple modification to the map in a reversible way (build a house and just stash your changes for example) that's harder.
If you're just seeking a branch system, it's way easier, you operate each "world save" as a commit and each world as a branch and that's it.

Merging on any of these occasions would require a full world reload, which at this dimension could be problematic.

The real problem is just the world size which at the current state should have around ~40GB if not using a custom save format.
To solve the problem above what could be done is to build a custom VCS service using something similar to Amazon S3 as storage.
In terms of cost, S3 should not be that expensive for this usage.

Reducing the save file in Wynncraft should be a "reasonably easy" task since you're running a complete custom world environment. There's a lot of stuff that you can throw away because Minecraft save format is made for fast writing and reading since vanilla requires a lot of chunk generation and reading. For example, saves operates similarly to how a hard disk works, in a nutshell for each chunk, it stores in the first bytes the size and with that, you can guess the rest, so basically it "never" deletes anything just write over it again and again and ignore data that is out of the byte range. Since Wynn uses a custom-built map you don't need this behavior so by properly rewriting the save file causes the empty/old data to be removed which massively reduces the file size in a world that exists for years.