Hey Gandalf, you stole my standard strategy !
Well, I never considered it to be anything special. I always thought this was the only way to play once you have baseships, and even worth considering for battleships and up. Especially in a larger/longer game where you have enough resources at some point and only need to build ships fast.
Drawback? Weakness? Not good against humans? I don't see it. If you cannot even protect this single system with the retrofit/repair/train facilities from an enemy attack, you would have lost with any other strategy anyway...