Those pokemon being bumped down won't really affect the BL tier, because a significant amount of BL pokes got bumped up. BL is the middleground tier, and as a result, isn't supposed to be played as strictly balanced as others.
The pokemon that got bumped down were the ones that were HUGE stars when DP first came out, and the metagames were still unsure. Now, does anyone really see that much umbreon or dusknoir? Since it i sbased on usage, its no surprise that they have gone down. And its no surprise that things like Smeargle has gone up, considering its recent ubiquitousness in the standard environment.
The only two that I really have to argue with are Hippowdon and Togekiss, because personally, I have seen very little decline in their usage.
EDIT: Also, just because something has been bumped down, doesn't mean it can't be used in standard OU. Since its based on usage and not ability to compete in it, some of the new BL pokemon severely outclass some new OU ones.s