We are still (as an agency) working with the 'legacy' map viewer. I was recently in the newer version, even though it's now just called 'Map Viewer' and noted that it doesn't have a 'Calculate' function on the field's themselves. Not sure if it's in there but it is sure helpful.
The other thing that has been missing from even the legacy map viewer is the ability to delete many records at once, unless I've been missing that as well.