I just thought I'd post this since I just noticed how insanely deadly Spikes has become in R/S. It now layers, so using it three times will cause your opponent to lose 25% of their HP every time they switch. Therefore, it's conceivable that you could just send in a well-defended Roar or Whirlwind user (Skarmory comes to mind) and just shuffle through your opponent's teams, making everything except Flying types and Floaters lose 1/4 of their HP. It also gives rise to another strategy: lay spikes, then switch in whatever is good against their current Pokemon. Now they're forced to either stay in and get destroyed by super-effective moves, or switch and lose massive amounts of helath, after which you can switch as well and just bring something that's good against their new Pokemon.

The only way to get rid of Spikes is Rapid Spin, and if your opponent lacks that, they've basically lost. To make the situation worse, there are only two Rapid Spin users that are immune to Spikes (Claydol and Delibird). I see two things happening due to this whole situation: first, Rapid Spin will become as essential on many teams as Haze was with the release of G/S/C, and a new cluse: the Spikes Clause. What do you people think on this whole issue?