DS has always been in the middle. It actually has become more of a pain as he's gotten older, but I can't justify moving him to a less safe spot just because it's more convenient. His safety is more important.
Now, I know that placing the seat behind driver/passenger is still pretty safe, but just for my peace of mind I can't justify compromising his safety just for ease of use, KWIM? I'm hoping to still keep him in the middle (he actually just switched to forward-facing this week, oy!) once baby comes, but we'll have to see if the seats will fit properly that way.
I have heard others say that for the seat to fit properly in some makes/models of cars the manufacturer will recommend actually putting them somewhere other than the middle, so you may want to check into that to make sure that the middle is safest in your particular car.