Remember that Pluto is essentially a big comet, and outgassing from the sublimation of the ice causes pockets to form under the surface. In a smaller comet, this leads to misshapen core bodies, but Pluto is in hydrostatic equilibrium (its gravity makes it round), so when these pockets form the planet will contract in on them. Contraction geology and contraction tectonics were expected, as were impact craters. That's what we are seeing so far, so this is kind of expected. BUT just because it's expected doesn't mean that it isn't exciting. This type of contraction tectonics can reveal a lot about the history of the planet because a lot of rocks of different ages are all exposed. The fact that this is happening at the scale that it is and that we can see it from here means that we will likely get a LOT of information out of this flyby. (also, I'd say that it looks a bit more like Mercury, which also underwent contraction geology albeit for different reasons)