You are incorrect on all counts.
First, the "you can't edit a file while it's open" part--computers would be less useful if we could not edit data, and the data has to come from somewhere, such as... a file. I will _assume_ what you really mean was something such as "should not have multiple, independent/parallel threads accessing the data when at least one is modifying the data, wihout some kind of locking and synchronization." This is a trivial problem to solve. The game already does it when it downloads a new world in the background to the cache.
Likewise, an update check and/or an update does not need to stop other things. I can have multiple web pages loading in multiple tabs; several files being transferred via FTP; several shell sessions, both local and remote; and so on. It is called "multitasking" in computers, even for a single CPU system which is technically only allocating CPU to one task at a time, but switching between so fast that it appears to humans as if they are all concurrent. ZK already does this as well, and it has a multi-stage loading process via the launcher.
How often do updates actually happen? It could be minutes between update releases, or many months. In the meantime, it is forcing the player to wait every time they want to play the game, exactly as in my case, the game kept crashing and needing me to start it again. Imagine if operating systems did this: "Your computer is booting. Please wait while it checks for an update before proceeding. Go grab some coffee while you wait..."
Back to MineCraft updates... You are not correct. It can, and does, update while running. That is why I used it as an example. Even the launcher self-updates. On rare occurrences, an update requires a full restart, and asks/alerts the user about that. It does not force it upon the user every time they start it, whether or not there is an update pending that would require it. There are numerous other examples. My operating system of choice is Debian Linux. Debian packages and the apt tool can and do update many things while they are running. Sometimes those things do need to restart after an update. Sometimes they do not. In my experience, ZK is the only one that seems to force "every time" in order to avoid "some times".
So you are trying to "explain" those "leaky faucets" to me... In a manner that is not trying to explain anything. You are trying to impose upon me that my opinion about the way ZK does things is invalid, and that I should accept it. You are trying to tell me that I should not post my comments in the comment section, despite the obvious: That is what the comments section is designed for. If you disagree, I am not stopping you from posting your own praise in comments. I am only responding to your negative criticism against my comments, as if I have no right to my own opinion and comments.
Same with regards to making a pull request; Pay me for it. I make a living by doing contract programming and consulting. The ZK team may do what they do without compensation. They make that choice because they are free to do so. Likewise, I am free to make my own choice to refuse to do so without compensation.
Furthermore, going back to the basic idea of improving the game... If the provides a negative or bad user experience, there is little or no incentive to "get involved" with it's development, regardless of compensation status. From the perspective of my profession, I actively encourage my clients to provide me feedback and comments: What am I doing right? What am I doing wrong? How can I improve my services and keep you coming back for more?
What I do NOT do is become defensive about negative feedback and tell them that they are wrong to feel that way. That would "add insult to injury", regardless of whether or not both or either was real or imagined. That would only incense and anger them more, making the situation worse. (I can go further in to this, as well: My background and education includes international communications and conflict resolution, not just mathematics and information technology. But this is already much longer than I intended to post.)