First latics kit I owned was the all red away kit from the Bovis sponsored days, loved it as a kid and been trying to hunt down an original with no success (grew out of mine at 8yrs old).
To me though, colour is linked to brand association. With them buggers at Old Trafford being one of the first things that spring to mind when the words "red" and "football", that brand colour is occupied. In cardiff's case, they have the welsh colours to reinforce the branding, but that would only mean anything to people that are welsh or have links to Wales. The idea that red will appeal to foreign markets via shirts and merchandise sales more than the blue (brand name link - the team is known as the bluebirds) is kind of flawed by the fact that Liverpool and United are globally recognised not just for football but also for being from hugely influential cities, leading to their popularity and brand strength. Outside of being a super huge club in 2nd tier football, what particular legacy has Cardiff got to re-enforce it? I'm really struggling to find anything other than Tom Jones and Torchwood.