I think that the following should be removed:
json-wheel - has been renamed to ocaml-json-wheel http://aur.archlinux.org/packages.php?ID=29860
mupad - isn't available from the company anymore (see last comment) http://aur.archlinux.org/packages.php?ID=3315
mupad-packages - same reason as mupad http://aur.archlinux.org/packages.php?ID=13128
pyyaml-python - has been renamed to python-yaml http://aur.archlinux.org/packages.php?ID=27758
skype_video_hijacker - has been renamed to gstfakevideo http://aur.archlinux.org/packages.php?ID=13956
libpsychrometric - project seems to be abandoned (download link still works though) http://aur.archlinux.org/packages.php?ID=13206
ww2d - seems to have been discontinued and when I ran it on my computer, it seems to be a 32bit only java binary? http://aur.archlinux.org/packages.php?ID=3451
ww2d-extra - the maps aren't offered any where anymore. http://aur.archlinux.org/packages.php?ID=3461