A second set of rear connections.
I think most RM owners would have powered speakers, or they are connecting to in-house systems, so the front connections are probably most convenient. However, a few XLR or even another DB25 or DB9 connections at the rear would be handy for those like myself wiring the RM mixer into a rack with speaker management systems and amps. I guess in the long term Presonus might eliminate the need for analogue connections with an AVB speaker management product.