From a dev's perspective, I think some of them are simply not interested in replying to some threads because of how crazy and wild this forum can become. Whether or not we want their input, you have to keep in mind that constantly dogging them about their performance doesn't make them want to come back to us, probably because a lot of replies to them can be really condescending or outright asinine. How would you feel if all you constantly got in terms of feedback was negativity and criticism? We've given them a lot of feedback on possibly improving the game, but at the same time we've basically pushed them away because of how angry/frustrated/upset we've come off as...then we become even more so after they don't reply as often as we want.
Part of the problem with their involvement here is that lot of us are assmad, raging nerds. Even if our arguments are valid, it can cause a good number of devs to feel anxious or discouraged, which can distort their context or give them really unnecessary pressure.
That said, the lack of Morello and Ghostcrawler is a bit weird. I remember before these forums became The Boards, Morello/GC/Xypherous would reply quite often and even ask how our lives were doing late at night. That's just gone now, which is really saddening given the point of these new Boards was to further that communication.
One last note: many devs do not post because they are either working (on something), spending time with their families, playing vidya games (they're nerds too!) or (probably) sleeping.