I just built my sump/fuge with the fuge on one side and the return in the center - i split off a portion of my return pump flow (rather than the drain)
there were a few reasons for this, and it took a lot of thought and many design changes to come up with this plan.
some of the things I was facing...
The largest of which was size constraints - the largest sump I had room for in my stand was a 15G tank, and at that it BARELY fits.
I also only have a single overflow downtube, so it would have taken some creative plumbing to feed the 'fuge sepratley from that.
not only did my "split" design overcome those two problems but allowed me to have relatively high flow through the sump itself, while keeping relatively low flow through the 'fuge, allowing a little mroe time for it's inhabitants to "do their thing" with the water as it passes through. I've read a few times that a relatively low flow through the 'fuge is advantageous.
my inspiration came from this article on melev's reef:
http://www.melevsreef.com/acrylics/sumps/e/sump_model_e.html
he mentions that the first model was "goofed" and used by someone with their skimmer body in the output section returning into the input section - this overcame one of my biggest space constraints, allowing me an appropriately sized return section with my skimmer output still "behind" a bubble trap. of course this made a center return absolutely necissary.
In conclusion, a center return does require some thought behind it's design, but can be just as effective as a linear flow, and even has advantages in some instances. I encourage you to check out all the designs on melev's reef and as many as you can find here, before finalizing your own design, as here are as many ways to set up a sump/fuge as there are reefkeepers, and many of them have offerings that may be just what you need.