If you see:"What does any other character bring to the plot? Maybe you'd like to switch Zoltan for Triss as well? Or Priscilla?" as a valid question, then I don't know what else should I do to make it more obvious.
lol, there's obviously no point discussing it with you.
Yeah, they could've done that, but why would they? Lodge sorceresses are already "established" characters. It would be pretty weird if they chose some unknow no-name mages instead.