Guild Wars 2

If you have a mesmer and does your magic it is all pink color effect it would be awesome to have the opportunity to change that, to what color you want even if you would have to buy it in the store.

hmmm, no.

I know why you are asking this, but part of WvW/PvP content is recognising what skills your oponent is using. The abillity to change the color means that would get significantly harder. Some skills are very much alike. How to recognise the difference between e.g. chaos armor (mesmer skill) and sancturary (Guardian skill) if the difference in color is gone??

So for cosmetic purposes it would be nice, but it would make pvp/wvw harder, so therefor I vote against it.