From and Old School SL resident that has been around for almost 15 years. Designers back in the day used 512 to reduce lag. They started with a 1024 x1024 template then reduce it to 512 x512. I don't think we need that much resolution. I think we need less lag, those of you that must have the detail don't complain about lag. How many of you look at your complexity or script counts ? How many of you notice you crashed or you can't move when Jo Smoe ported in. No it is not a coincidence. I for one am glad we can't import 2048.
Using Too Many Textures or Lots of High Resolution Images are the #1 source of Scene Lag!
The number and size of textures you use to texture an object or scene can affect the amount of lag someone experiences Lag is a slow down in performance of the viewer. If you’ve ever tried to move or walk and you find that your avatar isn’t responding as quickly as usual, or that everything just seems sluggish, or the objects in the scene look grey and take a long time to come into focus, that might be because there are too many textures, or textures that were too high in resolution!