I am not sure anyone is saying we shouldn't use the MLE at any point. I believe what Nick is trying to say (correct me if I am wrong Nick) The problem isn't as much spending the MLE as much as it is, what you spend it on. In a sports business model, age is just as important as the amount of money you spend. Committing the full MLE to Posey for example, in reality is a risky proposition. In sports (the business model we are all referring to) the older you get, the higher risk for injuries and rapidly declining skills. There is a chance that we could end up tying up 15-20 million for a guy that can't play. Where if you sign someone that is 25 or 26 that risk is diminished greatly, thus stabilizing your business model, improving your value, longevity and productivity.
Add to all this the fact that we have no idea that someone, anyone can't come in and have the same season this year that Posey had last. Thus freeing up more cap space and improving our flexibility at delivering a longer term and more stable product line.
While I agree that this year, you have a very good idea what you are getting with Posey (this basically can't be argued) You can't say with any honesty what his health and skills will be years 2-4 or 2-5.(Edit)33-36 years old