There are those who subscribe to top-down assembly (which is what I believe you're contemplating) and then those who subscribe to bottom-up assembly. Both have their pros and cons, and I seriously doubt any sort of concensus will be reached here.
Personally, I prefer bottom-up assembly (parts created separately then added to the assembly). The method that you're describing would result in numerous external references, which I hate. I've been bitten by them too many times to use them as a permanent feature in any part I create. I'll use them when necessary, but remove them as soon as possible.
If the parts you create are specific to one assembly, then top-down assembly may be the way to go. Maybe.
I agree with Jeff. Top-down can work well for unique assemblies but I prefer bottom-up for assemblies containing parts used in other places.