Tcl is good for interacting with a simulator (and other tools) for the same reasons Bash is good for interactive shells, and I think Tcl is the best tool for those jobs.
so like one instance I had is making a big input vector for running my testbench against. JSON, CSV, work with it in a dict or list, anything that I sort of already knew in python was better than what I cobbled together.
It's nothing against TCL, and it no doubt has the power to do it, it's just up I do FPGA stuff, python is my swiss army bludgeoning device. It's just like EDA tooling is like, the #1 place where I wish python lived, but it's TCL's stronghold.
What is the "could be" that you pine for?