I would not sell them.
Sell the Rotel and get a modern/new receiver with 150+ watts per channel with the newest codecs DSP, sound management and HDMI in/outs. Run HDMI from cable box into the receiver and out of receiver to the TV.(See Marantz, Pioneer Elite, Sony ES, Yamaha.)
Use a good aftermarket power cord 12 to 14 awg, and good cabling.
If you decide to add a center channel later you will be all set a sub as well may be useful for low freq. effects. It will all be easy to integrate with the addition of a quality receiver. You could also use the receiver as a Pre/Pro and keep the amp in the system if you really like how it powers the B&Ws. Just my thinking.