Agree on most of this; most systems I've used so far feel a bit clunky (Houdini has by far been the most sophisticated system I've worked in), and my sense is that if it had more mindshare / attention, the paradigm could actually be pretty fluid. Using most node-based tools today (including eternal), I get the admonition that it's like using text edit to write python compared to a pro at using pycharm.

The timeline thing is really key. Houdini does it in a sort of clever way where "time" as a variable is exported globally to any node that wants to use it, and the timeline feature is a consequence of using the time variable in any of your functions. i.e. it's not jumping you to a point in the program's execution, but rather acting as a controller for all time-dependent functions. sort of like exporting a time uniform to graphics shader