MarsSeed [1] filed a request to merge opencv2 [2] into opencv2-opt [3]: opencv2-opt is a better, non-conflicting package for the same.
[1] https://aur.archlinux.org/account/MarsSeed/ [2] https://aur.archlinux.org/pkgbase/opencv2/ [3] https://aur.archlinux.org/pkgbase/opencv2-opt/