Adding time estimation quickly.

Not from - to dates... you could skip that.
So you could quickly build your day/ week of estimated tasks.

I love the feature when time is visualized on the day task, but adding from and to dates takes time and clicks.
Drag and drop rearrange could automatically stack the tasks after eachother in time, but if you want you could overwrite exact dues and starts.

Here's a nice UI/UX from resource guru.
The coloured lines are showing the estimated length.
On the day header when you are over the date you can read the remaining free time, if not, you can see the scheduled amount.
Though I'd imagine it as draggable, resizable tasks on a day view, like google calendar day view. If not done the tasks would automatically follow the actual hour of the day stacking up below the line.