Nine out-Everywhered Seven's "Everywhere" promos with "Always On" in late 2014 and they out-Trusted "Trust" with "Sydney is Watching" last year, so I definitely think the Nine News Sydney promotional department have the potential to steal Seven's thunder again by taking their concept and making a better promo.
Personally, I think promotional phrases that Nine have used such as "the most experienced news team in the country" and "Sydney is Watching the #1 Newshour" are so much more commanding and powerful (and quite arguably, more truthful) than something like "What is Experience?" or the tired old "Make The Switch" line with promos that don't really say to viewers why they should be watching Seven's Sydney 6pm news over the equivalent on Nine.
But in any case, I think we're going to be seeing big promotional pushes (and possibly even relaunches) from the news services of both Seven and Nine in the lead-up to the start of the 2016 ratings season. While Seven may have clawed back some pride in the final few months of 2015, we're now in a new year and as we all know, absolutely anything can happen between now and the end of 2016!