It's got a big enough gravity well for Rosetta to have been orbiting it for the last few months
Sure, getting there, from Earth, was a long journey. Being dropped from 30km up and hitting a 4km target that inherently draws everything towards it, isn't a particularly impressive achievement. Coupled with the fact that all three retention mechanisms that were meant to hold the thing down on touchdown failed to operate, and the fact they don't know if they actually hit their target because they can't actually locate where it went... the only thing that'd make the landing impressive is if the lander's odd behavior was because it had been abducted by aliens.
Given there's dozens of computer game plugins that can do it at a click of a button, the math behind getting something from A to B in space is actually quite simple. The hard part is building and launching hardware advanced enough and reliable enough to do it, and to be fair, all the important hardware failed today so er... meh.