Price action over the last couple years has be higher, clearly. But, it has be steeply higher with no real consolidation - let alone a significant pullback.
This idea is longer-term (2-3 yrs.), and I fully understand that the index could very likely push higher to the peaks, if price action can break out of the . However, in my opinion, there is far more reward to the downside, and I would accumulate long-term short positions and hedge accordingly if needed.