I just thought about something...

Three of the four Twisted Guilds have the less/least-used class of its branch:
Firebrands- lolF/P
Nightshadows- Bandit
Windraiders- Xbowmen (though the Subi is weird...)

and it could be argued that Stormbreakers are Pallys (Lightning Charge), but they could just as easily be DKs.

Prolly doesn't amount to anything, but just my thoughts.

Stormcasters/Stormbreakers are a mix of all the warrior classes, mainly DK's since Lukan tells you they specialized in using Spears and Pole Arms.