Uh... what?
Rangers are called rangers for the same reason Aragorn (the iconic ranger on whom D&D based the class) was called Strider. They are wardens and guardians of the wilderness, who, as you put it "range about" to defend their charges against threats out of the wilds.
With Sorcerers; Sorcerers are at least as iconic as Warlocks, if not more so. Warlocks were a minor class in 3.5 which was released fairly late, and was only a core base class in 4e. Whether that means they are or aren't iconic is up to you, but it doesn't mean that they shouldn't be represented.
At the same time, Sorcerers are fun. I love Sorcerers, I love the way they cast spells, I love the idea of bloodlines. I'm sure there are a lot of other people who agree with me. I don't see why, as long as WotC gives an option for people who don't like Bloodlines, they should be restricted for the rest of us.