I just have one minor concern and one objection.

From my experience, not a lot of sitemods+ actually deal with the greenlight process (it requires some knowledge and experience not everyone is interested in and of course there's the risk of viruses, so it's totally understandable). Because of this, the greenlight process is a rather slow one, especially for mods. So I fear that expanding the amount of mods that need to go through the process will slow it down even more.

Another thing is that the foremost purpose of the greenlight process for mods is to catch those that are directly harmful to the community (viruses for example. MCreator is however not directly harmful). Not 100% of the submissions that makes it through are automatically following all the rules, but they will be safe for the members. Why is this important, it's because 99.99999% of the actual harmful mods are uploaded by level 1 members. Of course catching obvious spam is also what the greenlight process does, but it's not as important. Still, I would say that more than 50% of the spam mods are uploaded by members of level 1. So mods that could be caught by greenlight are for the most part uploaded by level 1 members.

As a side note, with harmful content I mostly mean harmful programs. You could upload a virus as a project, but those are way more obvious and won't get run by minecraft in the same way mods will.

So yes, it's a bit annoying that people above level 1 can upload MCreator mods publicly. But adding them to the greenlight process is in my opinion not the way to deal with it, since it probably can't handle the workload and on top of that it's not even its primary function.

Keep in mind, I'm no mod. My knowledge might be outdated.
I'm also NOT saying that this problem doesn't exist NOR that it should not be solved. It would be great if the greenlight process could be adjusted, a new process could be developed or more mods be introduced to it. I am saying that the greenlight process in its current state is, in my opinion, not the way to solve MCreator mods from people above level 1.