LFR didn't save raiding hell raiding was slashed for a few expansions after it was released compared to before. You gotta understand when blizz makes a statement they run it through PR first. Just like how they said there would never be a cashshop in wow because the game was to good for it.
ICC 10/25 didn't just have different items they had different ilvs as well. It was still the best you could get in the game but it wasn't one to one. I think you are confusing players farming certain high performing trinkets. It also didn't "destroy" 25 man raiding when you factor in three ten man guilds could fit into one 25 there was still more 25 man guilds.