It never ceases to amaze me how much my opinions seem to genuinely bother certain people. Both with my views on Stealth Rock and Items clause. Guys, all I'm doing is saying how I feel. There is simply no need for certain snide comments being sent my way.
In any case, I disagree that Items clause would be the death of Stall.
Leftovers
Black Sludge
Eviolite
etc. etc.
Those all all extremely useful off the top of my head. Oh, but you might say - only Poison Pokemon can use Black Sludge! Only NFE Pokemon can use Eviolite! Well, this is just another example of how Items Clause can help bring about more diversity in the metagame.
I'm sure there are many other items useful for stall teams as well. And it seems like there have been a bunch of useful items introduced for Gen 6.
Overall it seems like Gen 6 has improved the viability of stall teams compared to Gen 5.
So, excuse me for saying this, but if you feel that Items clause is a crushing blow to Stall teams, then you might just have to use your creativity more!
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Oh, and one of the biggest things I forgot to mention. Remember, Items clause applies to your opponents as well. So they won't be able to simply give all of their Pokemon Life Orb. That in turn improves the viability of your stall team!