There are couple projects that try to tackle this problem by providing an alternative CLI (on top of git's own plumbing), like gitless and g2. Haven't used any of them myself, but would be interested in experience of others.
I don't know about scaling, at least technology wise. Their trading web interface maxes out my CPU core at just 4-8 tx/s. And that's usually the time of big movements, exactly when you don't want trading interface to freeze up on you.