In etm2, past due tasks will be in a separate, "past due" view so you won't see them at all in the "day view". A small red icon in the lower right hand corner of the display will, however, appear as a reminder when there are past due tasks. You should easily be able to ignore that. ;-)
There will also be a "next view" for undated tasks grouped by context, e.g., errands. This corresponds to GTD's next category where you can keep tasks that can be done when you have the opportunity (you're running errands) but don't really have a deadline that you need to be nagged about.
The transition should, I hope, be painless. The new files will have the extension '.txt' instead of the current '.text'. You can make a copy of your current data directory, run the upgrade script in it and it will produce '.txt' files in the new format for each '.text' file that you currently have --- all without touching the '.text' files. There will also be a new configuration file, 'etm.cfg', so no changes will be needed in your 'etmrc'. You will thus be able to play around with the new version without affecting in any way your current setup.
I'm sorry the new version is taking so long but it's a complete rewrite and based on PyQt instead of wxPython so there has been a lot for me to learn and do. Still, it keeps me out of mischief.