Cracked wall, is it serious?
Just from the pictures it looks like a bad install.  The cracks look like they are rolled.  They aren't on any parts of the structure where there are two joints meeting or any sort of weak point.  They are basically right in the middle of a wood framed exterior.  

[Remember this advice is just based on me looking at a couple pictures and from what you said about inspection.  I am thinking that your inspector really looked hard on the other side of these cracks and found nothing.  They don't seem structural (but could be).  So I am really relying on your inspector doing a thorough job.]

How would I approach this?  First @Jack's comments are correct.  It looks like EIFS.  So I would get a couple of EIFS/Stucco installers out to get quotes on what they think is wrong and how to correct.  I am going to guess that there were installation steps or materials skipped.  A total guess would be that they left no expansion gaps for the insulation and that the insulation expanded and pushed out the finish layer.  

If the installers say something similar and quote you something now you have a dilemma.  This doesn't seem to be a huge thing.  But given they made a mistake here, it was probably made everywhere.  This is probably the first issue since it is the biggest continuous exterior wall.  

So I would go into this with the thinking that if it is an install issue then you might have more.  I would also figure out the age of the install.  If it is less than 5 years old I would think this waves can pop up everywhere.  If it is 10-15 years old I would be less concerned.  But really it looks to me to be a cosmetic issue and if you are the type of person that doesn't care about that as much, it really isn't a big deal.  Really this is why stucco and EIFS has more issues in temperate climates and is found more in the far south (or Spain and France).