Here are my thoughts:
The third option will add additional complexity to an already
complicated template tag and parser.
I like the first and the second. I guess I prefer the second, but that
might have to do with my programmer roots. I guess it would be
interesting to get some feedback from somebody with a less technical
background. We assume that an "English" style tag like the first
option is easier, and maybe that's true, but maybe the second option
is just as understandable. Anybody on this list have any opinion on
this? We struggled with the initial implementation of the get tag to
make it as readable and "English" as possible.
As for the Great Pipe vs. Dot Debate of 2009, I prefer dots but could
live with pipes. Pipes look a bit too much like l's (that's a
lowercase L). And it's more Python-esque, which I prefer to Django
template-esque, but see the previous paragraph.
P.S. I remember when the get tag was just scribbles on a whiteboard.