I am a few years the right side of the exit sign, so things may have changed, but can you be directly commissioned into an AEO or Crewman position these days? When I left, the direct WSO route was only for Nav's....
Just a general observation, but either role is what you make it, and you will get out what you put in. I didn't find WSOp promotion slow at all, in fact on the CH47 fleet, it was not unusual to be promoted as you rolled over the 5 year line - however, with one fleet in pieces after SDSR 2010 and one balls out in Afg, I can appreciate your perspective. If career, pensions and money motivate you - go WSO. If fun, job satisfaction and a relatively carefree existence appeal - WSOp is the way ahead.
I don't regret a day as Airman Aircrew (not a bleeding WSOp...) and wouldn't have swapped for a commission (other than Pilot). However, I was on the fleet I really wanted at a very interesting time.
Best of luck!