One important reason that the Classic worksheet is not evolving any more is that it's based on a cross-platform toolkit (StarView) from a company that has long since disappeared. Hence we are unable to port Classic to new platforms like 64 bit Windows.
The Standard Worksheet Interface has come a long way since 2005 and is used by thousands of Maple users daily. Different people have different preferences. Documents vs. worksheets. 1D input vs 2D input. That's why we allow you to configure Maple for all of those scenarios.
I personally use 2D input all the time but you can switch the default to 1D via a checkbox in the options dialog and many people do. Down the road, we'll look into providing a desktop shortcut that defaults to 1D, in order to make this even easier.
-Laurent, Chief Scientist, Maplesoft