I see your point, to a certain extent. The name Skywalker is especially odd. Why is it most of the Star War names sound alien or at least like exotic extrapolations of human names, but Skywalker is very clearly the joining of two English words. At least Anakin is a somewhat alien-sounding first name, but Luke is yet another common Earth name.
AT-ATs AT-STs? X-Wing Fighters? Y-Wings? B-Wings? R2-D2? C3PO? Why would people in a galaxy far, far away be using common Earth letters as acronymns, as descriptions of the shape of their ships, and as names of droids?
Millenium Falcon? Do falcons exist in a galaxy far, far away? For that matter, why do Humans in our galaxy look just like Humans from another galaxy, and why are the ones from the other galaxy also called Humans.
However, Darth Vader is a cool name. Knowing what we know now about other bad guy names (Darth Maul, Darth Sidious, General Greivous), it's obvious that Darth is a title, possibly a combination of the words "dark" and "death", and Vader could likely be short for "invader". However, when the name Darth Vader stood alone, before these other oddball names demonstrated a trend, it just sounded cool (and still does).
Yoda? I can accept that too.
Luke Skywalker and Millenium Falcon? Logic problems aside, those names sound cool.
Greivous just doesn't sound cool. Dooku just sounds too close to "dookie" or "doo doo".
Maybe Lucas's naming conventions have never been super, but I think the point is that they're gradually (or perhaps, rapidly) getting less and less super along the way.
