Sumo is better suited for vehicle navigation simulation as it mainly relies on grid network and cellular automata. Sumo has its own limitation for developing agent's flexible and rational route planning which is much required for pedestrian navigation.
In addition to Repast, you can also use MATSim. Both are Java based.
"VisSim" is a micro simulation model and can be used for modeling pedestrian. This can model all modes of transportation. VisWalk is an add-on to this VisSim model.