"Could rationality be run as a value? I'd tie it to the difficulty of implementation."The short, unhelpful answer: yes, it could. The short, helpful answer: no, there are better choices.
Rationality is difficult to pin down, requiring a meta-standard.
If we use a common definition of rationality, we get to the heart of the problem.
rational: agreeable to reason; reasonable; sensibleThis really just pushes the problem back. What does "reasonable" mean? Logical? Or just in accordance with offered reasons? And whose sense determines the sensibility?
Even determining that "rationality" reduces to logic, we can agree on the soundness of our reasoning, but disagree on the premises. Rationality works well in this respect if a particular chain of reasoning can be found to be irrational, but no amount of logic per se can prove a premise true, in and of itself.
Rationality, then, becomes "logical consistency" or "logical coherence" and functions more as a criterion than a value.
Rationality is an instrumental value at best, and thus trumped by other values.
If a resolution aimed at the education system comes along, then rationality as an end in itself might be a good value. However, most of the time, we use rational approaches to achieve other values--or to choose between conflicting values. This goes right along with the last paragraph above.
The reasons that actually motivate people may not be fully rational.
David Hume said it this way: "Reason is, and ought only to be the slave of the passions, and can never pretend to any other office than to serve and obey them." Blaise Pascal had another way to put it: "The heart has its reasons which reason knows not." We can use reason, in this rendering, to justify our choices, but our preferences that dictate those choices are inherently irrational. The bonds of family, the demands of justice, the whirlwind of love, the height of inspiration: what makes us human isn't reason, but passion. Rationality is cold and soulless and dehumanizing. (At least utilitarianism, for its faults, attempts to make happiness the core of public policy, rather than the abstract morality of pure Kantianism.)
Implementation is only indirectly related to rationality.
The second part of the reader's original question conflates rationality and practicality. In a negative sense, this is clearly defensible; it's usually irrational to promote or attempt something that you think (or know) is difficult to implement (or even impossible). However, there might be perfectly rational reasons for attempting something impractical or seemingly impossible: gaining political allies, inspiring future generations, signaling one's wealth or power, tricking one's opponents into a false competition. ("Star Wars," the U.S.'s ultimately fruitless attempt to install anti-nuclear weaponry in space, is sometimes credited with hastening the collapse of Russian communism, as the Soviet military diverted precious resources into wasted efforts.)
We return to the first objection. The difficulty of implementation can be measured by various standards, among them effort, funding, preparation, time, resources, and labor costs. If rationality is shorthand for "cost-benefit analysis," the precise balance of costs and benefits is a complex affair.
In short: rationality as a value isn't the most... well... rational choice.