A Plugin Marketplace and Labs Section

I think the most useful addition would be a plugin system, maybe with a Labs section where people can easily browse, install, and enable community-made plugins.

That would let users add features without making the core app feel bloated, while also showing you which ideas people actually want. If plugins are file-based, they should be fairly easy for users to install themselves, and the most popular, well-tested ones could eventually become official features.

Some examples could be layers, grids and measurements, smarter diagrams, reusable objects, presentation mode, better drawing tools, tables, richer export options, widgets, Kanban boards, timelines, and 3D viewers, Scenes / saved canvas views, just to name a few.