Piratecat
Sesquipedalian
Sure there was. It's generally a bad idea to name something with the same unique name when it works substantively differently. A 4e OA is different from a 3e AoO, and probably shouldn't be called the same thing."Opportunity Attacks"
There was absolutely no reason to change from the familiar Attack of Opportunity. (I have my own opinions as to why the change was actually made, but game-wise there is no good reason.)
That being said, my players mock this too.