After reading the wiki page for Data packs i realized it needs to be copied over everytime i want to create a new world. This could be frustrating for tech savage players, modpack onwers (who want to use vanilla functionalities to further customize their modpacks) or from people like me who doesnt forgot the head because its attached in the neck.
So i thought: "Why not implement a 'global' system similar to Resource Packs for that?"
When i say that i mean:
A way to store data packs for all saves (client) on a subfolder called datapacks (analogous to resourcepacks for Resource Packs) on the root of the profile folder;
In dedicated server you can set what global data pack you want to use via a line on server.properties called data-pack=, exacly behaviour of resource-pack= (From wiki: "A default resource pack can also be set on a server by changing adding a link to a .zip file download after the line resource-pack= in the server properties file. Users can still opt out of using the resource pack or choose not to download it though");
In client: a menu identical to Resource Packs would be available, where the player can tick what global data packs he want to activate. Like RP menu the bottom entry is a disabled one representing vanilla, and the top also is locked to represent any possible datapack embed in the world folder (the vanilla way).
For reference this is the vanilla Resource Pack screen, without any RP to be activated (for DP imagine two entries: the "Default" for vanilla data AND a "Embed" for any possible data packs stored on the world folder).
I agree, since when experimenting with them (and 1.13 Rift modloader mods) I just find datapacks in the save folder to be nice and not too bad, but it can get very tedious very quickly and reloading datapacks can be a pain every so often. I'm probably too used to modding so the client just does what it can to load them and off I go, especially since I make small custom modpacks most of the time, and 1.13 instances are a breeze, with both datapacks and mods), I don't mind going to wikis to find out how some of the more larger/content datapacks work, since I'd do the same with mods or more in the mods case I'd have a recipe viewer, or check the Minecraft wiki on what things I might need a refresh on things in the game for. But global datapacks just seems better, mods can, even though they are unofficial, resourcepacks and saves and otherwise get their own, 'major or global folders', how hard are datapacks to be global I'd like to know, or does that make things more fit into the unofficial territory for whatever reason or its apparently too difficult to pull off, then that makes sense and I wouldn't question it further? Since most computers need a bit to get later versions of the game working or even when modded, so these extras can't be too bad, 1.13 datapack & modded combined instances work fine for me so far after a week of experimentation and understanding of both (1.13 modding being a more niche side of the modding community as of now just like any new version of vanilla getting mods is until the big ones come over).
For me experimenting with Rift mods (1.13 modding instances until 1.13 Forge, so a placeholder/fill in until then) as well as Datapacks on the client, ("EXAMPLE INCOMING" encase people misunderstand since yes I understand what this idea is about) Rift mods appear in the resource packs menu since it doesn't have a Forge Modlist menu/Mod Options Menu button (not in the resource packs folder but appear on the menu like the resource packs screenshot you have above only the mods listings are greyed out like an incompatible resource pack or incompatible saved world (content and code tweak mods/quality of life are all listed, so not only content/asset mods are mentioned); and mentioning the mod names, also Rift mods also get noticed as datapacks for some reason when you check the datapacks list command results?) Either way I know I'm jumping between what exists for one thing, and is somewhat unrelated and what would be a nice idea and actuality for another (what Rift mods do either intentionally I have no clue but the methods are there so...) but global datapacks I'd love, and also would work out since I want Twitch Datapack instances if I can't get Rift modded instances since its a 1.13 thing (Rift is brief placeholder until 1.13 Forge, it will be phased out, but still) Datapack instances I want to be easy and convenient if players/makers want others to experience them or export to friends or something. Global datapacks just makes things easier for players but probably not for creating? If the unofficial community created methods exist, I don't see why datapacks can't. Does it break some policy or something for community assets or ideas to be global or something maybe? If its a struggle to get it possible I guess but it clearly isn't impossible, and must be a stability thing maybe Mojang are considering? I don't know. But eh, they only just got 1.13 and 1.13.1 done with save specific setups so like it is in their mind right now for them to be global anytime soon, all well I guess. I'd like to see it happen though. But still I know I'd want global datapacks like I do with mods, but the modding communities and the vanilla communities get and want different things so, eh. Just thought I'd mention what I know from 1.13 experiences players have and what I've witnessed by using both Rift mods and Datapacks for about a week or so (Datapacks for about a week since still new to them, Rift mods for about a month, and they both work well together from my experiences at least).
I do have a video on Rift mods appearing with the datapacks list command results as well as the resourcepacks menu, I know you meant another menu but just for the sake of what I've experienced and what shows up; but its not uploaded as of yet anyways, and I'm questioning on uploading it really, but for the sake of fitting with my experiences and what your idea is, I might post it.
Screenshots: (I know its a different thing since its 1.13 mods not datapacks, but eh, its an example, I've explained it, might as well as show what's done by something that has put things in place (even for a 1.13 Forge placeholder) where it can display important lists without creating extra buttons like the Mod Options button, it uses Resource packs menu (not the resource packs folder to detect this) or displaying mods in game text on the splash screen since it doesn't do the whole Forge Mod Options Button other things, its uses Resource packs and Datapack list to let you know what's in your modded instance)
Rift Modloader using Resource Packs Menu, Not Folder To Mention Any Mods Accessed By The Client
Rift Modloader Mentioning Content Mods along side Datapacks in List
True but to me anyways accessibility of them is nice. 1.14 'Datapack Loader' allows for Global Datapack acknowledgment/use, I haven't used it much yet though so I'm still working how good it is for client/resource packs noticing as well as at the moment, but yes probably more for clients than server I 'think' I don't know much about it yet. But yes server or client setups, server.properties settings or not can be an issue with datapacks, I do agree with that.
And yes multiple worlds can be good or bad for datapacks placed in them/configuring them, /reloading the game and other needs, in client or server situations.
But either way, they are asking for what mods do for datapacks and while I do see the appeal and yes have enjoyed 1.14 datapacks globally right now (not sure how many roadblocks it could have, I'm testing it as I go to find out for sure), I don't really see a wrong side to them in each save even if it can be tedious or for familiarity/other reasons of convenience/limitations. I understand why Mojang did it the way did though besides what it seems/what I've said. I just suck at saying it that's all.
Datapack Loader Mod Spotlight for 1.14 18w50a using the Fabric Modloader:
Good call I guess, no clue if they will add global datapack support (I think MCP has datapack support already but I don't know in what way, I'm no developer), but Fabric has data loader for global datapack support and some Fabric mods use datapacks while Forge (no matter the state it is in) doesn't seem to be ready for support like that any time soon so we will have to wait and see. At least one modloader is ready instead of none. Forge will get it's stability and be it's proper self again but for now it's not going to be ready at the moment.
No clue how long Forge 1.14.2 will be until it's finished since 1.13.2's wasn't and 1.14.2 is just porting/working out things as they go yes but for what exists now use that and wait for the other to be in a proper state instead of public beta for much longer.
I know it's no server properties setup this mod, just a global datapack folder for the client, but ask the fabric team and they may be able to help with a server with mods and datapacks. The All of Fabric servers I think run both Fabric mods and datapacks I think, since I've not come across any of the mods having an more achievements aspect so I'd assume it's a datapack on the server globally.