"nostalgia" and "did not need change" are just excuses to keep the familiarity of something. These textures were dated and desperately needed change. The pixel artist has grown as a pixel artist since the conception of the original textures, and Mojang is making the mature decision to look past this familiarity and make textures that not only look better but overall have better pixel art technique. As a pixel artist myself, I am very glad to see what Mojang is doing to the textures, and its something I wish they'd done a long time ago. But that's just my opinion. If you like the old textures, just use a resource pack. It really changes nothing.