I don't know many of these examples you complain about, but it's true that for big realms with enough military strength to bully their neighbours, it should be all about searching for an elaborate RP or IC excuse to declare war (or make its neighbour declare war on it). But it would be just simplistic; this is a game of intrigue and politics too, and I think over time it's been created a quite rich background that maybe just feeds many players, who enjoy improving endlessly their realms.
Of course it's really amusing warring, and when wars involve huge realms, war is something that can provide fun with not too many awful consequences for any of the contenders, since they're too strong to be destroyed by the other easily. I don't know exactly how has been your experience in the realms you've quoted, but maybe you should have picked weak ones to start, if you didn't. If you pick huge and crowded realms just because you expect to be quickly crashing cranes, you've got some chances to be disappointed. But small realms I think usually face which in my opinion are the most exciting wars, wars for survival.
