Aww, poor girl. Her head is MASSIVE, although that is probably partly from the fact that the rest of her is so irregularly thin.
Only you know what you have the means to handle, both training and money-wise. Were you thinking to get her to ride, or simply to get her and keep her as a happy, well-fed pasturepuff pet? That would probably affect your considerations. She probably wouldn't make a great jumper or dressage horse, but she'd probably be fine as a trail horse - if you can find a saddle wide enough for her.
And I can't think why she'd have trouble assimilating to the other horses simply because she is a draft...aside from normal herd issues, which can often be worked out.
Of course, I don't have a lot of knowledge about drafts either, but that is my relatively uneducated gut reaction, so take it for what it is worth....:p