Hello,
I know that the Gantt Diagrams are still in Beta as of today, but something that I feel should be implemented is other time scales for projects. The "day" scale is pretty standard, but sometimes I find it useful to be able to scale work on a half-day or hour basis.
Most large projects can't rely on this diagrams because of the lack of a proper calendar, so I find it most useful for sketching projects, or quickly making a short planning without worrying about workload/calendar/etc. And for that purpose, I feel that scaling with hours, or half-days, can be useful.
Edit: An easier way to do something like that would be to, instead of "days", have "units". That way, an user can have more control over said units.
For example :
unit Hour
unit Day : 8 Hours
unit Month : 30 Days
unit Week : 7 Days
'The two following tasks are identical
[Task 1] lasts 16 Hours
[Task 2] lasts 2 Days
'Same here
[Task 3] lasts 168 hours
[Task 4] lasts 21 days
[Task 5] lasts 3 weeks