I think this is exactly what Kralkatorrik's personality is. Acting like the Elder Dragon he is; menacing, world ending and thinks that everything is beneath him, that there is not a need to communicate and to understand his intentions/plans. This is also the same for the other Elder Dragons, everything is just a means to them and the destruction of the world around being just an after effect of their true goal - which is to consume all magic. What made the first two Elder Dragon's interesting is that they had champions or agents that communicate with us. Unique among them are the agents of Zhaitan and the Sylvari which Mordremoth corrupted. And i think, i could be wrong here, they chose to communicate in some form because they see us as a threat to their plans. While Kralk just doesnt care and goes about his business as usual without so much letting us know what his motives are making him bland in that sense.