This kind of work is OK for some simple block level circuit designs. In the real world designs, as circuits grow complicated, and parasitics add in, the SPICE convergence issue kicks in and automation becomes difficult.
In a way, do all these different side effects make automation even more important? Modeling them doesn't sound easy, but I would imagine that our mental capacity for evaluating solutions is the real bottleneck here.
I think even if you don't account for all of the side effects, you can still use these tools to develop useful circuits which you can then use to design real-world circuits.