Unless you're going for a mixed attacker 6 IV is rather pointless, you're better off sticking with the tried and true 31/x/31/31/31/31 and 31/31/31/x/31/31 spreads. and to answer your question, no the breeding mechanic has not changedDid they change the breeding mechanics in X/Y?
I have a 31/31/x/31/31/31 parent and a 31/31/31/31/31/31 parent breeding right now. Destiny knot is on the 6 IV one (male). I am trying to go for a flawless egg but I can't ever seem to get 6IV. Do I have to reset the game after each failed egg now because it really seems like the game should have thrown me a bone after 200 eggs. Wtf?