Hi Damon,
You can download max 2 files at a time because in Windows, the limit to the maximum number of connections that can be made to a server is 2 by default due to HTTP/1.1 specification. This means is that if IE (not effects Firefox) makes three calls to the server, the third call will be blocked until one of the first two is finished. Thus you noticed that you can not change to another folder during downloading 2 files at the same time. However you can increase the maximum number of connections for IE by adding some registry settings, please see the below KB article for the details:
How to configure Internet Explorer to have more than two download sessionsNoted your suggestion regarding download queue and folder upload/download.
Yes, the multiple login issue is by design but there will be an option to disable it.
I have sent you the details about upgrading your license via email.
Thanks for your feedback.