It certainly is a huge improvement, if you're running multiple locomotives, having cruise makes all the difference in the world. 
I'm confused about the width being an issue, the board is the same width as the DCDR it replaces.
The length is where the usual fit issues arise. Another issue is the connector placement, and the extra 10-pin connector. Finally,there's the large bridge sticking up in the middle, that is frequently where the wires were routed for the DCDR. I know in the Camelback, the connector positions dictated a lot of screwing around to get the CC-M in. I actually had to remove a connector from the motherboard for clearance and hard wire some stuff.
