Hey @Fhireman,
Have you seen the new session state app that was released with the 0.84 version of Streamlit?
This session state app has an example of a to-do app that is much easier to code with the built-in st.session_state object you now have access to! 
I like your ideas around the + and - buttons of the number input! Did you know that community members can request new features on our Github issues? 
If it’s something you are really keen on you can request it there, share it around and if it gets enough support the Team generally looks at how feasible it is to incorporate the most popular suggestions into Streamlit! (we are very receptive to community involvement and suggestions!)
Happy Streamlit-ing!
Marisa