That doesn't make a lot of sense to me. If you define some performance criteria and the processors on which those criteria must be met, what's the problem? The operations would be the same, the instructions underlying those operations could be different. For any particular processor it could even be slightly inefficient. But at least it would be secure to an agreed upon/openly vetted standard. As I said, if you just want a fast/insecure PRNG, make one separately, and give it a very clear API name indicating that it's insecure.
The only problem I see is where you draw your entropy from if you need to mix in something truly random.