Okay, I waited until you finished posting to respond. Here goes.
The following is a bit confussed because there a couple of confused issues being combined into one pack.
Personally I think that the issues that are getting confused "download and install", "choising what you want to play with this time in the game", "modding mods" and "the dll".
I am currently playing test games where I a switching between three different Shinto Religion mods, two of which I am supporting. I do this by going into three different MLF's and changing 0 to 1 or vice versa. We need something that will make this switching of mods on and off easier - but that is another "kettle of fish" or can of "worms to feed" said fish.
I think WoC planned on making a GUI for modules, but that was before their "staff" all left. I'm sure you could make one with python, I just am not familiar with it enough to do so.
Afforess, you are providing two services. You are the provider of a mega-modmod download and install thing, and you are building new mods and converting other mods to RoM. This is further confused by other modmoders making and merging and updating other mods and modmods for the current version of RoM.
I don't disagree.
dll (SDK) verses Python composite verses XML composite modpacks (including graphic XML modpacks)
By their nature dll or SDK mods have to be merged into one release since they end up in the same dll.
The merging and control over these needs a librarian (that's the industry term) whos job it is to ensure that the correct version gets combined and released.
Options for turning on and off the components needs to eb available to the players in many cases.
Python composites (Python and XML).
Python is not modular in the Civ environment. However much work has gone into getting it as modular as possible and some work is still being done. Currently the issue here is one of making sure one Python mod "plays nicely" with other python mods. In particular the config/init.xml needs to be managed else people may end up with errors because they are only loading part of what they think they have.
In a "normal" IT environment this would again be controlled via a librarian and the players would get everything.
Currently we only have python mods by Afforess and Civ Fuehrer and installation is done by them so as not to break each others mods. I have three python mods on the go and would like to add them sometime. This will complicate things more
I guess I've been doing that to the best of my ability. Both of those are major concerns in the modmoding community.
XML composite modmods
There are hundreds (or at least twenties) of these. Currently the composite MLF is handling this, although I was not aware of its existence until its installation broke my testing
You're never aware of the effort that goes into that, until of course, it breaks down, and someone looks under the hood. For the MLF, it's fairly simple. But for larger thing's like Dexy's modmod's, I had to add "If (GameOption...)" code all over the place. I just hope I caught them all. That's why I released a beta so soon.
What the player wants or the bottom line
Unreasonably

the user wants one download to hold them all! I am not sure that is possible. That is where your discussion is at.
I want to download them all as well. It was a surprise, and a bit of a pain to get GeneralStaff's modular civic buildings to work, at first. Any user without any modding expierance would have likely given up immediately. That's why I make installers, so user-friendly.
But my question is this:
Should the modmoding community unite under one banner, a "modmoding standard" installer, with everyone's creations? But that is exactly what I mean either... Just lumping everyone's work into an installer isn't the same.
My point is this:
Look at my guide on the OP, the Modder's Guide to Afforess's Modmod. Look at all the XML additions I've made. I'm sure everyone here can envision new modmod's which can use them, especially the tech yield, commerce, happy and health changes. I can keep adding more, too. If modmoder's just stick with RevDCM's sdk, they lose so much possibility and potential. I feel that there are untapped gold fields of modmod's there, waiting to be made, with those new attributes, but I lack the time, creativity, or patience to always make them. It's just such a tragic waste to let them be us-used.
That would be the "banner" or new standard.
Of course, that's why we would need a community installer, everyone would need to use my/our DLL.
I would like your mods + other peoples mods in one big installation program in which you and pick which mods you want to download. If this is called "A New Dawn" then that's what I want. I do not want all the mods combined into one pack where you cannot choose which ones you don't want to add. For instance I do not want a pack in which I cannot "uncheck" the sea monster mod from my list of modmods to install.
I hope you understand what I mean.
Yes. You want customizability. That is my core principal. I never have or will force a modmod on anyone.