Why would anyone start using 'LOL' anyway? I have a few problems with it:
a) It no longer states that the joke/what happened is actually funny, but that you aren't bothered to say anything else.
b) Not really a problem but it looks like a person drowing. (lol) Geddit? The 'l's are hands and the 'o' is the face
c) Acronyms are useless in the first place.
Come up with a new system? If anything your idea is flawed, not the metric system. You would have to get this approved by every federal leader. Make the effort, to come up with a new system, sure... but do you really think a government will take the time to do something like this?