Well granted I'm used to old school Karnor's, but I think your "social" yell for help radius is a wee bit high here.
level 30ish, engaging entrance you will aggro .. I think 4-6 of them come, which.. there's 2 at entrance, and 4 on each upper deck platforms.. 2 from each upper deck platform, and these mobs are probably mid 35-45ish.. Maybe consider tweaking the guardians yellfor help radius, because with that fixed the first castle area is doable with a group of 30's. I tried to lull them but lull didn't work in the end (sadface).
don't nerf this much if any, it isn't that it's a huge challenge it's just inconsistant in difficulty with the rest of KC. Hehe.
After that initial pull, it's pretty easy to do the castle. The second area isn't too bad unless you get a named, I was dinging like crazy here once I could break the first pull.
This is with BRD/CLR/ROG/WAR