How do base stats differ between classes?

I was reading a forum that said the Warlock class was "squishier", a "glass cannon". Is this true? How was anyone able to tell the difference?

What are the base stat differences between the classes (Warlock, Hunter, Titan), and how are they measured? For instance, how does health or base damage output differ between classes? Or if the "agility" stat is equivalent across several classes, is their agility the same, or does the class add a buff? Or is calling the Warlock class "squishier" more about the way their ults/super powers deal damage?