If those could be fed equally well (i.e. doubled decode width, reorder buffer sizes, register file ports), not much would be different, of course, but, from what I understand, that's significantly more expensive (given that the complexity of some of those things grow at O(n^2) or so (bypass network, connecting all pipes to all others? picking out the ops to run in a given cycle from the reorder buffer?), vs O(n) from just increasing width), so we probably won't be seeing 10 SIMD ports anytime soon.