Perhaps you should take your own advice, Mr. AC. Here, I'll help =)
Thomas Henry Huxley said:
Agnosticism, in fact, is not a creed, but a method, the essence of which lies in the rigorous application of a single principle...Positively the principle may be expressed: In matters of the intellect, follow your reason as far as it will take you, without regard to any other consideration. And negatively: In matters of the intellect do not pretend that conclusions are certain which are not demonstrated or demonstrable.
Philosopher William L. Rowe states that in the strict sense, however, agnosticism is the view that humanity lacks the requisite knowledge or sufficient rational grounds to justify either belief: that there exists some deity, or that no deities exist.
So, agnosticism (even agnostic theism) holds that rational understanding is worth more than blind faith. How is this not a "rationality-based belief system?"