Great to hear you have already played with custom objects 
In regards to the other features mention:
- combining streams => it’s in the backlog, hopefully we’ll get to in it the next weeks
- deleting branchse => it’s there already but hidden (we’re due to improve this) see this issue
- uploading files to the viewer/server => this is not on our roadmap, what file formats were you thinking about? We have discussed internally supporting uploading IFC files
Thanks for all the feedback and ideas, they really help us make a better Speckle!
If you’d ever want to share with the rest of the community what you have done or are doing with Speckle we have a showcase category. And if you’d like you can Introduce yourself 🙆!