Steelix will probably move back up to BL or OU because of Curse.  Curse+Roar is just the most amazing combo, and he gets STAB Gyro Ball people!  Anyways, I think this will help Steelix much more than Bullet Punch on Scizor, atleast in standard.
Nasty Plot Darkrai is stupid.  As if Dark Void + Bad Dreams wasn't bad enough for your Resttalker, now he gets +2 Special Attack when you switch out and a STAB move without an immunity.  Foul.
Scizor's viability in Ubers just increased for several reasons.  First of all, he can switch into Darkrai safely assuming it already put your status absorber to sleep.  Secondly, it can SD as it Nasty Plots or switches out, and then abuse the low physical defense of Ubers with a 90 power priority move(after STAB and Technician), and hit the slower of the Ubers with a powerful X-Scissor.  Scizor will likely go up in usage, but it will still lose to the same things.  Now it doesn't have to run Light Screen / Roost / Pursuit to beat Gengar, but it gets destroyed by Skarmory and Weezing.  Using Bullet Punch>Iron Head has its advantages, but it does beat Weezing, which Bullet Punch can't accomplish.  I think we will see a huge rise in Weezing if people begin overusing Bullet Punch.  
What I am truly looking forward to is the possible new berry and Cursing Steelix.  The berry damages the opponent if they use a special attack against you, and since Steelix has a huge base defense stat AND Curse to work with, it is likely they will attack the weaker special defense.  Now, phazers are typically an issue for physical sweepers, and Skarmory could easily foil this, but Roar destroys Skarmory.  Roar always moves last, just like Whirlwind, but since Steelix has Curse and naturally lower base speed, it won't be able to be Phazed out.  This is yet another reason why the rise of Weezing may be approaching.  If Snorlax ends up getting Slack Off, look out, Weezing says hi.
EDIT: 
	
		
	
	
		
		
			Cursing Steelix could be useful in UU. 
 
Also, Probopass has STAB Power Gem, which means Power Gem could theoretically see some use now. Yay for special rock type moves.
		
		
	 
Really?  Steelix will surely not stay in UU...