They comment on things when they have something useful to say. What do you want them to say about the topics you brought up?
Ads - "We figured you wouldn't like the adds but we wanted to increase crown store activity so we added them anyways."
Jewelry Crafting - "Umm sorry it's grindy, working as intended, have fun!"
Sloads - "Working as intended; L2P."
Based on their history, IF they decide to address people's complaints regarding a specific topic, it will likely be only after they've decided on a course of action. Not sure how 20 threads are better than 1-2 threads that are kept active.
And lets be honest, people don't want them to just comment, they want them to make the changes their asking for. If ZOS commented just to tell you that they weren't planning on changing anything you're asking for, I'd be willing to bet you wouldn't be happy about it.