I don't think that IMG bundling in Joan with other models was necessarily racially based and like someone else said, my guess is that this has probably happened with other models. It is juicy information to know, but I don't see it as sinister if they only do it with a very small number of high potential girls. IMG knows quality when it sees it and I can't see them playing this card* unless they knew they had a model who, at best has star potential and at worst is a clothes hanger, namely someone who has a good walk, looks good in clothes and is professional. When you think about it Joan's success is evidence that, if done right and with the right girl, this practice can work out very well for all involved.
ETA:
* Plus I wonder if it plays out as if the designer wants Sasha, Freja and / or Lara then they gotta take Joan, or if it is more along the lines of if the designer casts one or more of the stars from the IMG board then they get a high potential newbie or two for free or at a discount.