How on earth could someone say that Couture is not a legend...
Sure he wasn't the greatest fighter and lost his fare share of fights but the guy accomplished things few could dream of and had an extremely long and fruitful career. He beat Liddell, Belfort and Ortiz in their primes and was was champion of the HW division(weak division or not that is still an accomplishment). He was constantly counted out of fights but found ways to win or at least make the fights competitive.
Couture fought the who's who of MMA, Horn, Randleman, Barnett, Rodriguez, Belfort, Liddell, Lesnar, Nogueira, Machida. Those are quite the names(especially at the times that he fought most of them).
He isn't legendary for being the absolute best fighter but he is legendary because of everything he accomplished and for what he did for this sport.
As for Machida, no. He did help put Karate on the map and has beaten some tough guys but he still has a long ways to go to be considered a legend in my books.