Been experimenting with it. And it dont looks like there is any direct negative affects by relocating the capital, like the negative affect by changing faction hair, where the ex-hair get a bad trait.

SO to sum it up, you should always try and move your captal so that its in the senter of your empire to reduce corruption and increase order in your empire.

However, when relocating the capital I try to keep in mind the following. All new familiy members will start out in the capital, so I try and choose a capital that has some good infrastructure that will help to educate my new familiy members before i send them out to their own settlements.