Not saying they'll do it, but I think shows that remove sexual tension have to do something to keep the relationship interesting.
Are viewers going to care about Korra and Mako going out to dinners, kissing, etc? So either they break up, we think they'll break up for some reason, or they advance the timeline.
eta: Though they did make Sokka and Sukki work, but I suspect more so because it was a side plot to the real shippyness of Katara + Aang.
Edited by sciborg2, 24 June 2012 - 12:45 PM.