The fact that Liseberg has kept two ferris wheels and three tower rides going has always struck me as a bit odd. The older wheel is very pretty at night when seen from in front of Hotel Gasten and the counter service fish and chips place, but I've never done it because Lisebergshjulet made it seem pointless. Presumably a lot of their guests think the same way. The S&S towers do offer slightly different experiences to Atmosfear, and both times I've visited I've made a point of doing them. The average guest won't know that though, going straight for the tallest, and they're poorly presented and quite out of the way on top of the hill so I won't miss them much.
It'll be interesting to see what they add to their already strong collection of flat rides in their place, and if they're going in the same loctions how they'll ensure that guests keep making the journey up the hill to them when the 'new factor' wears off.