@jonatan I appreciate your excitement.
As I may have mentioned before, the biggest feature of this module is around making a good page building experience for non-technical people and making it easy to setup as a developer.
"Page builders" in my opinion lie on a spectrum:
On the right end you have things like Webflow which is 100% visual and infinitely flexible (let's put aside the fact that it's also a CMS and remotely hosted). It's an amazing tool, even though I don't use it because it's not how I develop. It's a great system, but requires design skill and you have to make sure you are consistent across the board, stick to a style guide, etc.
On the left end you have what I will call section builders. Perfect examples include RepeaterMatrix and ACF Flexible Content field for WordPress. I made a video comparing the two in my WP vs. PW series. This approach was probably the go-to approach from... 2010 to 2015? It's much less "flexible" in that at it's simplest form, a section like "image left, text right" will always be as such and unless there are other sections to choose from, you are stuck with it.
In the middle-right you have things like Gutenberg, Elementor, Brizy, etc. This is where most of the development action is, thanks to reactive JS frameworks (same with Webflow).
In the middle-left there are tools like N1ED, Froala Blocks and others.
The way I see it, ProcessWire is a tool geared for developers, and developers can customize it perfectly for their clients. A big part of this is a good page building experience and (a) after having built dozens of websites with RepeaterMatrix and (b) experimenting with different approaches and (c) trying to respect ProcessWire's way of doing things, I have concluded that the section builder / repeater matrix approach is the way to go. It just needs to be improved a bit. (also, I'm lazy and would never be able to program a visual page builder like the fancy ones out there because my JS skills are embarrassing)
First, why do I say it's the way to go?
Because it's regular ProcessWire, you can do multi-lingual, while not a big deal for me, PW seems to be a favorite for multi-lingual websites. So that's important.
Because they are normal template files, a matrix-type that has been used multiple times can easily be modified by editing the template file (requires the developer obviously).
Because it's regular ProcessWire, you can SWITCH from one matrix-type to another and retain your data. This is pretty important.
Because they are normal template files, you can technically load them directly on other pages that don't even utilize repeater matrix and just inject your own content.
YOU CAN DO DYNAMIC CONTENT!!! Well other page builders are doing this more and more, but with ProcessWire, you can do it much better (I'll elaborate on this another day and how my module will do it).
I just don't trust non-technical people to create a good looking page from a bunch of sections by dragging and dropping and having too much flexibility. Fonts being mis-matched, colors all over the place, responsive thrown off. This is why I don't like page builders like Gutenberg, Elementor and the like. They look very sexy in the beginning and might be OK for people with web page creation experience, but it gives too much flexibility and web pages are complicated when you consider responsive design, image sizes, etc.
I can use my CSS framework of choice (UIkit of course) instead of whatever internal CSS framework each of those builders relies on.
So, what problems do section builders currently have (like RepeaterMatrix)?
You cannot "preview" a section in a slick way before you add it. Sure, the matrix-type might be named "text left, image right" among a sea of 20+ other matrix types, but this won't stand out, especially in that smashed together list of matrix-types that you get with RepeaterMatrix. Non-technical people are VISUAL, so getting a preview of what they are about to insert goes a long way. My module has solved that problem as I posted in that above video (it's changed a bit from that video in a much better way).
You don't page the benefit of instant feedback of what a section (and overall page) looks like as you populate the content. Again, this goes back to the visual nature of people and the soaring popularity of page builders like the ones I mentioned. Given ProcessWire's strict separation between frontend and backend this also gets complicated because ProcessWire's philosophy is about keeping the two separate. However, the true way around this is to use something like ProDraft's Live Preview feature. At this moment in time, it doesn't autosave + live preview changes to repeater/repeatermatrix items, but I've asked Ryan if he could add this (post is here; not viewable if you haven't purchased ProDrafts). He said it's possible and hopefully one day it will be there. When it does get developed, this in my opinion solves the visual feedback aspect of section builders.
As a developer, it's annoying to have to continually re-setup repeater matrix for every site. It's not easy to share the template files across various sites which would be ideal. Also, you have to code your own matrix templates and add all the fields accordingly. As a content editor, you want flexibility in the types of layouts... what if you want your "text left, image right" instead of "image right, text left"? Because you can't physically drag-and-drop those elements, then we are forced in having more section templates that address the most common cases. Therefore my module solves this problem by providing 200+ section templates out of the box (and growing). It also provides an alternative (more visual) interface by which you can register those templates into the repeatermatrix section builder fields all from the admin (none are registered in a fresh installation... you choose what you want, so this avoid bloat). And it feels very to the ProcessWire admin interface (a pet-peeve of mine are plugins in WordPress that have their own garrish, bloaty graphics... example: https://wordpress.org/plugins/wordpress-seo/).
The important point here is this: content editors / non-technical people / whatever you want to call them therefore no longer have to worry about dragging-and-dropping layouts, potentially messing things up. My belief is if you provide them with a good set of options, they will find what they need, choose the matrix type and then just focus on the content. ProcessWire's backend is all about having a good content entry experience and the ideas I've played around with have evolved around that concept. We want non-technical people to focus on their content and we as developers should not have to worry if they uploaded a 20mb image, because the matrix template will take care of that.
Give me a couple weeks and I'll make a video.