While true that getting close enough to the city to make it load into high priority starts tracking more NPCs, it isn't that much of a difference. The game is already keeping track of all of those NPCs anyway since very few if any city dwellers are marked as "no low level processing". OCC does not add any extra NPCs, so you're already tracking them all anyway at some level, all the time. There's also not that many actors that hang around outside the cities anyway, so it's largely a moot point.
There aren't that many scripts on city NPCs either, and the scripting engine is one of the few extremely efficient chunks of code. You'd need thousands upon thousands of them to burden the system at all, or perhaps one with a really terrible set of commands, but it takes a really messed up script to get there. None of which exists on vanilla scripts.
If you're not running OCC, then no, the RAEVWD module is not redundant.