Network does not effect quality of regens.
It merely effects where you get your regens from.
The larger the network, the larger the area you sign players from. A small network means you sign players from your city. Slightly larger means you sign players from the region. Larger still from nation, and so forth until you get continent and eventually world.
If you look at top clubs and their networks, you'll notice those with the largest networks have more regens from different nations than top clubs with medium recruiting networks.