clearly SK can handle more than 4 knights at once so why not bring in an SK version of raids, large group(scaled down) dungeons, 5-8 man level sets
in other MMOs large group encounters and raids make up the bulk of endgame stuff and they are pretty good fun
So even though it would be a big undertaking making a few big group level sets (3-4 depths each, like boss levels, possibly playable in multiple tiers) would add some great group/endgame content (unlock access at certain rank?)