OK, I just solved this issue and wanted to follow up for anyone out there who may experience this.
To recap, workbench would run very slowly whenever contacting the server. Processes would take an everage of 90 seconds to open. Most 'browse' dialogs had a 10-20 second delay.
The issue was caused by the permission groups assigned to my profile. Livecycle was scanning all of the permission groups each time I would hit the server. Deleting the groups and assigning permissions directly to my profile solved it. Processes now open in under 5 seconds.
So, if you are experiencing performance lags in workbench, check out your user profile on the server (adminui).