Not just that, but also the 50mm air restrictor that it's burdened with kills some top-end power. That was all part of the "negotiated" rules in 2008 when they were allowed to bump the twin up 200cc over the size of the I4's.
I dont think top end power or any power has ever been a problem, from what I have heard getting it to the ground was.
Now the last report I heard was that, that had come ahead in leaps and bounds and now it is ready for some serious testing