I was directed to this forum by the affinity twitter after sharing the inspiring work of @_baku89 in building procedural vector drawing tools with scripts (see below).
interactive web demo
This feature might take the form of a "Code" persona or "Code brush" tool that allows people to write or download short scripts to modify or create procedural content. Having a fully featured and public vector drawing api (such as the html canvas / svg etc) would allow users to build tools for other users (like copy-pasteable plugins) and i imagine lots of responses to current feature requests such as blendshapes etc would simply become "someones made an af script for that".
I understand this is a non trivial / long term feature, however there is a whole (growing) industry of creative coders (myself included) that I can see rushing towards this type of tool and helping develop exciting new drawing tools for other designers that cannot code (yet). This would literally be a game changer in vector drawing apps and someone will do it eventually. I just really hope Affinity Designer does it first.
Ps. If you allow "Persona's" to be developed as native affinity plugins you might find that someone will do most of the legwork for you..