Hi @DJrax - as someone who enjoys building, I love all the ideas. That said, as I've shared with the community before, new build features just aren't something that you can expect to see included in Stuff Packs. We have a different group of engineers who work on the build portion of the game, and their time is allocated entirely to the larger packs, and to free updates to the game.
With that in mind, don't lose hope. Just look to Game Packs and Expansion Packs if you're interested in new Build Mode features. :) I'd suggest posting in the Ideas Corner section of the forums, or in the subforums for GPs or EPs.