Well Mikey - you have to take into consideration how much money it would actually take to REALLY be a help for the refs, and that kind of money (as Beaker said) is not likely to be spent by anyone at this current time, so NO it would probably not help refs much at this point - seeing that the level of filming would probably be really poor!
Actually - IF the filming is not at its best, then it would actually only do more harm than good! I mean - if the refs had to take the filming into consideration, then they would probably in some situations have doubts where they normally would just make the call then and there!
EDIT: And that without even being able to see the situation in it´s full - due to lack of angles being filmed!