You're entirely incorrect. Whilst I, as many others, was hesitant to use the new viewer due to its drastic user-interface change it is actually a massive improvement in many respects. One of the areas that it hasn't touched at least in a negative aspect is network and bandwidth lag. I reguarly use secondlife on a sub 3Mb/s internet using viewer 2.5 and both my network and internet speeds in general are consistant with viewer 1.23.
;-) Don't hate on progress.