I'll limit my criticism to what I'm familiar with: AFL (although I hear bad things about video replay in rugby and soccer as well, but that may be due to a reve

I'll limit my criticism to what I'm familiar with: AFL (although I hear bad things about video replay in rugby and soccer as well, but that may be due to a reverse survivorship bias kinda situation). AFL is a somewhat unique sport, and whilst the video replay system is admittedly improving, it's initial implementation was poorly thought-out: they didn't use cameras with high enough frames-per-second to actually catch the detail that was it's raison d'etre. From one frame to the next would miss the 'event' proving whether the ball was touched by a player, or rebounded off a post or whatever else may result in something other than a goal. The fast pace of AFL also means that where video replays are used are in the, generally, less controversial sets of decisions that umpires have to make. Goal umpires have been pretty well vindicated by the video system, whilst it's traditionally been the quality of the field umpiring that gets questioned, but video replay is not, and cannot (due to the pace of the game) be used to remedy this. I should say that I think cricket has got its various technologies nice and tight, along with tennis. But they're not pure video replays, they're additional technologies built on top of video.