If you distil this down, it's actually a common feature in many apps that include a calendar or calendar-like view. It's just that you have to think about it as a recurring task not some entirely different feature.
An example is Google Calendar (which in the view below is similar to TDL's Week Planner view, but the concept would be similar for the Calendar view).
The key is that each recurring item allows you to customize individual recurrences to change their attributes. The previous app I used allowed this too. I found it extremely valuable, but unfortunately it was kind of clumsy to use in that app. The Google Calendar implementation of this is particularly good although I have seen others that are good too.
If you set up a recurring event in Google Calendar, you can then change the attributes of either all recurrences at once, only the currently selected and future recurrences or only apply the changes to that particular recurrence. Here is the dialog you see when you try to change the attributes of a specific recurrence of an event.
After you set up the recurring item, you just delete the individual recurrences you don't want, and/or change the start and end times of the remaining recurrences to suit your needs. Note that when you delete a recurrence, you get the same dialog shown above that you get when changing a recurrence's attribute. You can delete just that recurrence, that recurrence and future recurrences or all recurrences.
You end up with this, which I think is what you are talking about. I set up a daily recurrence and then simply deleted the recurrences I didn't want and changed the start and end times of the ones I wanted to keep. Each of the recurrences is the same event.
In addition, each recurrence can be dragged around the calendar to change its start and/or end times or even dragged to a different day. Very nifty and efficient.
So this is really just an enhancement of recurring tasks, making them more flexible and powerful. And I think it satisfies your "time blocking" task management use. In fact, in TDL, if you are lazy like me you could say conceptually that ALL tasks are recurring tasks. The ones that only occur once are recurring tasks with zero recurrences. 🙂
PS: I am not implying this would be easy to implement! I can't even imagine how difficult it would be! It's way beyond my
paygrade! But yes, it's also on my wish list and I think a very productivity enhancing feature.