For those of us who aren’t Aristotle or Kant, by far the best way to regiment our philosophical thinking is subjecting it to the criticisms of others.
But, of course, it's certainly the case even if you are Aristotle or Kant; the Aristotle we know is the result of spending a vast amount of time in Plato's academy, followed by the formation of his own school. And while Kant tended to socialize better with people outside the field, he also extensively interacted with others on philosophical questions in important ways (Mendelssohn is the most obvious example).
* I think there are signs that Weatherson is conflating features of the academic profession with features of the practice of philosophy (e.g., the substantial constraint point); to which I would say, as you would expect, so much the worse for the academic profession. Career is secondary to good thought (and the diffusion thereof). But that, of course, is a common enough conflation, and understandable. On the other hand, 'barstool philosophy' does not sound pleasantly social to me; it sounds quite the reverse, namely, unpleasantly failing-at-being-social!