I agree it’ll probably have to be third party developers and we’re seeing that. Short cuts (originally third party “workflow”) is already pretty powerful. If you play with Audulus[1] you see a UI not too dissimilar to Dark except for Audio Synths instead of programming.
Both obviously need to be greatly iterated on, but the bones are there.
Considering that they barely managed to design working "regular user interfaces", the next-generation editors and development tools won't come from the teams currently working on iPad OS.