I've been reading this thread with interest as I bought a Ridgeback World Expedition 26" two years back for a RTW tour so thought I would sign up just to share my thoughts and tips, especially seeing as one of the posts above was mentioning if it would be specced suitably for a RTW trip.
Firstly, I bought the 2014 model for my trip which was back when the bicycle featured cantilever brakes so can't comment on what the newer hydraulic disk brakes are like although it would be recommended, if touring well off the beaten track to switch to either mechanical disks or v-brakes (although v-brakes may not be possible if the mounts are not included on the new frame of course.) From the original spec there are only three things I would recommend changing for a RTW tour.
1) The saddle: Quite an obvious one but the stock saddle wasn't anywhere near comfortable enough for a three year journey so I swapped it out for a Brooks B-17 (so comfy
2) The rear rim: The stock rims that came with mine are Alexrims Downhill rims. These are notorious for cracking on tourers who take heavily loaded bicycles on poorly maintained roads or just general dirt roads. If you are sticking to touring on asphalt in developed countries, they are safe enough but if you are planning on a bit of an adventure I would highly suggest switching this rear rim out. I was able to find a heavy duty Sun Rhyno rim and a 2010 Shimano XT Hub (back from when the components of the freehub were made of steel) which ended up being bombproof for 40,000 kilometres over a hell of a lot of awful roads under 30-55kg of luggage (depending on water and food requirements.) In comparison, my front rim which I kept as the stock wheel cracked after 33,000 kilometres with barely any weight in my front panniers.
3) The rear rack: I actually decided to leave the original aluminium rack on my bicycle however and it amazingly lasted me over two years with a lot of weight on it until it finally cracked. It's actually still going at the moment, but might need to be replaced soon I reckon as it is currently held together by a tyre lever and a wrench
Welding aluminium is a lot of hassle in many parts of the world so I would just recommend buying a steel one from the start.
Hope the above helps is anyone is thinking of speccing the bike for some rough terrain/a very long distance journey. Let me know if you have any questions on the bike as I have plenty of experience with the thing by now!