When you go into Packages, and then Manage Package:

We sold a few of them a while back, but it defaults for the week:

Is it possible to show all ACTIVE ones or something?  This way, our Managers can assign an appointment to the package?  

Unless there is another way to do it?  We tried creating an appointment, and assigning it to the client, but then it doesn't minus it off the package.  So it's hard to tell how much the person has left.  The only place we have found to be able to add an appointment to a package is within this dashboard inside packages:

And to get to that I always have to SET the date range back a long way back.

We are facing the same issue. Adding/managing appointment from the backend is too much hassle.

Yes.

It's probably best to also make it so that when you schedule someone for an appointment using the Appointment tab, perhaps it'll have some sort of pop up that says, "Do you want this session to be included in their package? and then it can give you a list of packages that client has already purchased..." and select from there, and it can minus it from that package.

Or a simple fix for the time being is when you click on Manage Package, the DATE RANGE should be all time or filter by OPEN OR CLOSED / CANCELED packages.

I think every manager wants to see all the OPEN / ACTIVE packages available.  This way, we don't have to go back in time (and adjust the dates) just to find if someone has a package or not.