//www.planetminecraft.com/css/fonts.css?v=iAIAFChsfiOXhFo1Q2xw8K3yBUtVao3WmHpU39GNnyc7p4lg,//www.planetminecraft.com/css/style.css?v=T9kVa_mNK4oqqiO_-HxUaBfhD1IRVxgYoh1A2x5t8Ij5BGJm,//www.planetminecraft.com/css/editor.css?v=JXg2qF5v-S8uAfYd4r9DPF80sC4h3eHDH-K6Fyux5F5ZWhVm
MEMBER
default
Categories are often used to split up the different branches of the same big tree.
But modded datapacks and vanilla datapacks are their own separate trees altogether - even though they are both trees (tree in this case being a datapack), they work on different environments which most of the time isn't compatible with eachother (a modded datapack might modify something vanilla itself doesn't have, for example), and hence can't be considered branches of the same tree.
From an user experience point of view: If you're someone who has no idea about the technical things that can be done by vanilla datapacks, you'd assume modded datapacks and vanilla datapacks as one and the same (since they're both categorized as "datapacks" at first based on the site's current design), only to then install a modded datapack in vanilla and be confused about why it doesn't work, or vice versa.
Assuming I correctly understand what you mean, having at least a filter setting for those that require additional software (Optifine seems to be a commonly sited example) would make sense.
Whether an entirely seperate subfora is needed is more debatable as there may be those who prefer having only one place through which to search.
[Which again brings up the issue of overlap between various sorts of game modifying 'things'.]
Bye the bye, this probably shoud be filled as a suggestion ticket if you find any reasonable level of support…