I actually really like Tcl, I like the simplicity of its command argument nature.
The thread "Why is Tcl syntax so weird" was posted a couple of weeks back, https://news.ycombinator.com/item?id=29143346. The first comment on the page includes "Tcl is still a wonderful language and I often lament how it’s mostly died out". Happily, for me at least, it's still going strong in HDL land :)
I use VHDL, not used Python. My understanding is that Python will be many times slower than VHDL, so verification tests that take the best part of a week would then take several weeks with Python. And being dynamically typed is fine if you are running a script that returns quickly, but what about it borking even hours into a simulation, when you can catch most dynamic type errors with stronger typed languages at compile time. Python doesn't look like a compelling replacement for VHDL, unless my understanding is off.
I guess Tcl is just one of things that divides opinion.