It definitely doesn't sound normal, though it may not be anything DN can control.
We were having similar issues with certain areas of the admin and business hub (even before 8.004) but, after some troubleshooting, we were able to determine that the password vault we were using (which was a browser add-on) got an update that started conflicting with DN for some reason. We are now in the habit of disabling the password vault when using DN and we are no longer experiencing the slow loading. When we exit DN we re-enable the add-on.
You might try disabling any browser add-ons one-by-one and then testing to see if the load speed increases to try to determine if one of your add-ons might be causing a conflict and slowing things down.
I'm trying to mark 70 jobs as dispatched from one of my stores and its taking ages to complete, literally go and make and drink a cup of tea whilst its still spinning. Only noticed this happening today though.