A novel partial Colorless-Directionless-Contentionless and gridless ROADM architecture using a MxN Wavelength Selective Switch (WSS) as a base building block is proposed. The MxN WSS allows us to create an interesting trade-off between cost and features in a contentionless environment. An argument is placed for a partial CDC-gridless ROADM architecture that is of a lower cost than all other combinations and achieves almost similar functionality compared to a full CDC design. Extensive simulations verify our claim over three different core network topologies as well as test our architecture for 100Gbps transmission requirements.