The banal talks in Kingdom Halls are simply microcosms of the banal offerings in the wider "world".
JWs like to think they are not influenced by the world, yet other religious groups and the "secular" news media are also dumbing down, using more sensatrionalist writing styles and cutting the length of articles. I attended a Sabbath service of a Seventh-Day Adventist friend of mine recently and was struck by how simplistic and banal the message was. This contrasted vividly with the Sabbath services I attended in my youth.
I'm not mimimizing the appalling paint-by-numbers talks in the local kingdom hall (a thirty-minute yawn fest) but the more general picture is one of simplified and simple-minded approaches both in religion and secular arenas. Sadly, the JWs are not alone in eliciting bored-out-of-the-skull yawns.