This unwanted dithering might be caused by Photoshop mapping pixels to the nearest palette color in an area where it's pretty much 50/50 between 'rounding' to yellow or black so it goes yellow for one pixel and black for one besides it although it might only be like 1rgb value higher or lower. Not sure how to fix that, I'm not that familiar with Photoshop.
I actually think most patterns will be indeed better of using the old way, but textures are very handy for extremely complex stuff or placeholders until someone finds the time to make a vector version.
I actually think most patterns will be indeed better of using the old way, but textures are very handy for extremely complex stuff or placeholders until someone finds the time to make a vector version.