I love the idea of Sage, and think an open-source state of the art CAS is essential in this day and age, but in trying to master it I got sick of Python.

I truly, honestly loathe the way Python handles for symbolic computation, and digging down I traced my disdain all the way to the fundamental object model of Python; so there is no way some surface-level modification will work for me.

On the one hand, it allows the sloppy "integration" of various systems (like you mention). On the other hand, it is not a real integration, just a patchwork of the worst kind. You never know what kind of interface you will face next, there is no coherence among tools, everything is its own world and you need to translate manually between them. Assuming you know the interfaces beforehand. If not... good luck.