I dont understand the context of the question either, so ill just say that even the books admit that "casters differ" and they do differ, because they have a different job to do. So comparing them is apples and oranges. On the things that they could be compared, like swordsmanship, id say that the average assassin would be better, perhaps, compared to the average warrior. Red Caste training is thorough and extensive but lets not forget that its training aiming to produce, in the very end, military units. Warriors fight as a unit in major battle engagements. Now assassin's training is more selective i believe and more detailed (if it werent it would make no sense to kill failed candidates, in order to safeguard the training "secrets") cause it aims to produce a man that will have to, in most cases, carry out a very specialized job, that of assassination, all alone.
Having said that, and being a dedicated Red Caste my self when i was roleplaying, ill just add this: assassins? kill em all