I've become a little concerned by all the reviews saying Prince Caspian is even more violent and action-packed than TLTWATW....

That certainly doesn't align with the book from my memory at all.
I am glad it's doing well though - anything that turns more people onto C.S. Lewis's work (even if it's a loosely-adapted movie

) is okay in my book. Hopefully we'll get the chance to see it soon!