I agree with the necessary boost in guard level and overall strength, but there's another major problem that I have run into, when i was defending NC around 8:00 last night.
I had killed an intruder of my lvl(17) and for some reason he had bound to the rift shard IN the NC barracks, which made it literally impossible to have him leave, because everytime i killed him, he came back.
What I did next is completely spawn camping, but I killed him 11 times after my first kill on him, each time giving an option to leave NC, each time he "declined" by casting an IGMS at me, which then i killed him again.
The name of the intruder was "Gandlor Ster" or something like that, only thing i remember is "Ster"----maybe Gamblor was his first name.
My idea for a fix is to make, #1 the rift shards in a hostile faction completely unusable by enemies, seems to be pretty easy to fit that into the storyline, and faction lore.
#2 I support making raiding a faction a huge undertaking, with a REQUIRED amount of lvl 18+ players at about 3 or 4, making teamwork necessary unless a single person were to drag single guards at a time. I think that "raiding a faction" is a joke at this point, because it should be impossible for me and Downfall together at lvls 15 and 17(or 18 ) to attack dwarves and live past the front gates, despite his awesome character build, and we even got to Tag and Lag without me dying more than once.

(And that was because of lag)