New "DCS" control system selection

I am seeking cost effective solutions for replacing my Rosemount System 3 control system.

I have decided that using remote I/O multiplexers for the HART smart analog and 120VAC Discrete I/O provides several significant advantages. "Home run" twisted pair cables from local area junction boxes would be replaced with an open protocol, high speed industrial Ethernet like Profinet, or Modbus TCP/IP to a server/HMI. While researching this over the last 6 months, I have discovered several multiplexer/controller solutions that are are rated for Class I, Group II environments.

The current list that I believe are strong contenders include Delta V, MTL MOST (Now GE Fanuc), Siemens S7 & PCS7 and Yokogawa Stardom FCN. I invite other suggestions. There are numerous features that I would like to see in the "open" system such as OPC or OPC UA, redundant hardware, easy to configure and troubleshoot, an inexpensive historian attached to the company LAN and minimum Licensing fees. I am inviting both pro and con comments, either directly and via this forum, on selection of a new cost effective "DCS" that would be a true distributed control system.

I feel this open discussion could also provide help to others with older control systems. My I/O count is over 1000 points. A spreadsheet comparing features of potential candidates would be of strong interest.