User blog comment:GothGirlXenon/Is Cartoon Network Ruining Total Drama?/@comment-11883116-20170820093210/@comment-4742462-20170820150535

The request for the couples to be broken up came from Teletoon in order to teach kids that "First loves don't always last". And while I'm not sure if the love triangle was the writers' decision or if that too was a network request, the writers did at least come up with the idea to canonize Gwuncan (which Tom McGillis initially had cold feet about). All this info is from the "Behind the Drama Part 2" video from a couple years ago.

While they may not request poorly written episode scripts, they do make requests that make certain episodes worse. For example, they wanted Owen's cameo in the finale of All-Stars.