I think 'epic fail' is dying out. I'm pretty happy about that. There was a time I was worry about it getting very popular and I would have to go underground. I thought the fact that there was House episode called 'Epic Fail' it was going mainstream and everyone and their mothers (and by extension my mother!) was going to be using it totally indiscriminately. Luckily I was wrong.
So I hate the expression 'epic fail'! 'Why' is a good question. There's some degree of gut-level repulsion, but that's not really a good explanation. I don't have much of a problem with the use of 'epic' (though John Milton may feel Paradise Lost cheapened by a comparison to a truck carrying cinder blocks rolling over). So that leaves us with with 'fail'. I like that considerably less. I have no problems with a little linguistic creativity, but the misappropriation of 'fail' as a noun when the word 'failure' is totally there to do that job seems outright lazy and for some reason really repulsive.
But this isn't the first time this happened. Back in 2002 or 2003 I was on some pokemon message board and apparently some guy in an IRC channel used uttered the fateful words 'CALM MIND SUICUNE HAS NO WEAK!!' and it become an object of mockery, making its way into several signatures. I thought, 'man, look at this doofus who can't even use the word 'weak' properly'. I really wasn't playing any contemporary pokemon games at the time, but shortly later I read some team ratings (these are when you post your team of pokemon with their moves for use in competitive battles and other users critique you.) and the first one I looked at started referring, in all seriousness, to 'weaks'. I looked at more threads. More 'weaks'. I've never seen the movie, but I imagine the effect is something like the end of Planet of Apes when they see the buried Statue of Liberty and realize the bizarre world they are on is actually Earth. Apparently, the mockery of the quote was not the word misuse, but the hyperbole.
So I think the overarching theme here is that I sort of get in disbelief about the popularity of these sloppy linguistic constructs that really don't add any new expressiveness to language. I don't see why something like this would spread beyond more than a very small group. The whole perceived phasing out of the expression is another interesting wrinkle that I'm totally not complaining about.
And yeah I have no idea why Calm Mind Suicine has no 'weak' either.