NCIS: Los Angeles really is filling the void that was left by The Unit when CBS pulled the plug on that franchise in May. Fresh, exciting action-packed drama with interesting characters and fast-moving writing. You really cannot ask for more.
LL Cool J has been doing very well in the first three episodes portraying a believable character. You may not hear his name called at the Emmys next year, but he has certainly leaped into the acting field a lot more successfully than Ludacris, for example, whose "performances" are as wooden and completely scripted as they come.
I am okay with Los Angeles focusing on some of the supporting cast, but it is clear the best dynamic for this show is between Chris O'Donnell and LL Cool J. Giving too much time to the lesser characters could deter viewers.