This. 100% this. I was basically trying to articulate a similar view, but perhaps not doing it as succinctly or clearly. 
My hope is that the seemingly-logical (to me) splitting of tasks into separately tracked things can be done but avoid most of the downsides: keep it intuitive, reflect changes into a parent entity, and perhaps at the end roll it all up into the parent entity (destroy children but preserve work notes back into parent somehow). A fuller articulation of the downsides of the splitting approach would help inform possible solutions.
As one example of a know problem here, getting comments together in one place seems interesting to think about. I don’t know that the contents of Comment Fields can be operated on in formulae at present, likewise Rich Text. But I can imagine something like concatenating all Comments from Child Entities into a single Rich Text, with e.g. labeling and dates for each, so you’d have a single Comments stream but still have it delineated what is what. I previously proposed a “Conversation Field/View” and some interesting discussion resulted. If such a view existed, it would be ideal to be able to pass it “messages” via scripting, so that you could end up with a nicely formatted and consistent result for a situation like this. Likewise just spitballing here. 