It's okay but I think it's been happening often. It should be rare.
Like lets say the DU hair being base game now. They could have tweaked the "dread braids" a little on to the side, make it look a little bit messy. Baaaam - new hairstyle from old hair.
If they are going to add DLC stuff to the base game they should add new swatches and/or tiny little tweaks to make it look a bit less DLC so simmers who bought that DLC don't feel like wasting their money and basically paying for other simmers' stuff, if you know what I mean. You pay for something to have in YOUR game and then others get the same exact thing for free. If they change it a tiny little bit it could feel less wasteful. If only for one person :D
