Based on my previous post, I'd like to expand on why I believe Stealth Rock deserves at least a suspect test if not a ban.
Firstly, most people have said that banning moves has never been done and so can't be done.
People, everything has to start somewhere. Even people when Pokemon was introduced said: "Playing pokemon has never been done before and so can't be done".
The argument is invalid simply because precedents always start something. You can't do something without starting it right? At some point we have to start, why not now than later?
Secondly, a lot of people feel that other moves like Earthquake could be considered broken.
The difference between SR and Earthquake is that Earthquake doesn't Chop off 50% before you even start! This means that faster Pokemon can always outspeed and get a chance to strike back.
I would like to at this point define broken as a concept: a factor that differentiates Pokemon by viability to such an extent that it overrides simply too many other factors to the point that a Pokemon, despite having potential, is largely untapped in usage because of said factor. This factor is also a factor that to a certain extent imbalances the metagame to the point that certain playstyles which, with the absence of said factor, would be viable, become impractical. Said factor must also be distributed widely to the point that there are a large number of ways to spam said factor and that these ways outnumber this factor.
In this sense, Stealth Rock is broken because it overrides too many factors(Base Stat, movepool, role played on a team, ability to counter in new ways, room for creativity) on multiple Pokemon. It also fits the other criteria because it makes playstyles like Hail and Sun impractical and helps Rain dominate.
Take an example in order to further illustrate the definition: Darkrai.
Darkrai had high stats but had a differentiating factor which overrode the whole metagame: Dark Void + Bad Dreams.
Dark Void affected every Pokemon in the metagame: no immunities.
Also, Bad Dreams effectively meant that the Pokemon would not only be asleep but also would suffer damage, combining two statuses at the same time.
In this situation, rather than looking at number of Pokemon which would be inappropriate, examine the number of sets that could carry this: all. Every Darkrai set, from Support to Special Attacker, at the cost of one move slot, could easily carry this move and render one pokemon ineffective.
This is the simple reason why Darkrai was broken.
Just like that, I believe Stealth Rock is also broken.
Regrettably, smogon does not publish a moves usage stat(or at least not one I am aware of) so we cannot see just what percentage of competitive teams have at least one SR setter.
I would like to now draw attention to the advantages of a playtest.
Firstly, the worst possible situation: Dragonite, Salamence, Volcarona become broken, Sun teams become broken because of Volcarona, no increase in usage of Ice and Bug types. We then revert back to SR and no damage done. Is there any loss from doing so? No, not at all!!
Secondly, the best possible situation: Types like Ice and flying become more viable and check the dragons which were feared to be broken and volca, playstyles like hail and Sun become more viable, rain dominance becomes an equalized metagame with more room for creativity.
However, some people still are against the idea, claiming there is not enough time. Well, I think there is more than enough time. We have SIX months before X and Y, it's not like X and Y are releasing tomorrow :)
Another alternative might be to cancel the TM Status of Stealth Rock, thus severely cutting on the distribution of SR. I like this option for a couple of reasons. This is the list from Bulbapedia:
Geodude
Graveler
Golem
Onix
Steelix
Roggenrola
Boldore
Gigalith
Dwebble
Crustle.
Firstly, while not completely eradicating SR, this option means that no longer can pokemon like Chansey and Blissey, which do not need SR and have no right to it, spam SR.
Secondly, the above Pokemon will see considerably more usage, which can only diversify the metagame.
Thirdly, pokemon like Articuno would be more used, but at the same time, pokemon like Drago and Sala would not be broken because of the existence of setters.
However, I still prefer the banning of SR(the second option is more moderate, but doesn't completely eradicate the issue) and would heartily welcome a suspect test without SR.