diana and vi op

Diana requires a skillshot to land in order to be able to dash more than once, and said skillshot can be avoided. In addition, her dash is targeted on enemies, meaning Diana can't use it to escape enemies or get out of a teamfight or dodge abilities unless enemies are positioned correctly - once Diana is in your team she has difficulties getting out.

Vi's ult follows you, and vi is pretty good at locking people down as a result, but that can also be a downside. If Vi ults you and you disengage, then she'll be in the middle of your team on your own. Her ult also functions in a way that supports and other teammates should be able to CC her right after she finishes her animation as she also can't control her own actions during her ult.

Vi's ult is just another version of Nautilus's ult. Guess he's OP too :l

Fun fact: Nearly every targetted dash follows the target. This includes irelia, maokai, pantheon and many more. One of the few that does not do this is fizz dash which due to this got a special interaction that it does no damage if you flash out of it.