This is being tried in the counties and the fielding captain or batsman can refer to the 3rd umpire. Each team has 2 refs per innings. If they get it right the retain the two refs if they don't they'll lose them.
I think there should be negative consequence for referring a correct call and it should be like if the fielding captain gets it wrong they'll lose one of their drinks break and if the batsman gets it wrong the batting team will lose a over. Is that too harsh?