You make a good point about absentee voting being
a tradeoff, between enabling the vote for those
who couldn't make it to a polling place, and
reducing the assurance that ballots are cast in
secret.
An idea ... it seems that one important element of
a proper election is the secret ballot, and that this can best be done by having the ballot cast in
a controlled public and publicized place - so that
the public can see that ballots are cast in secret
without the opportunity for coercion.
But this doesn't mean that all ballots have to
be cast locally. How about something analogous
to a Public Notary, which is a low tech answer
to a vaguely similar problem.
In the case of elections, it would mean public
voting places, at which you could cast a ballot
for any election, anywhere. A separate and
unbiased (er eh ... is such possible?) organization, perhaps one of several selected
competitively, would operate polling places,
at announced times and places, open to inspection
by all parties, ensuring ballots were cast in
secret, using electronic balloting to enable
the submission of a ballot for any election being
held that day.
This would solve (in a low tech, 'good enough' way)
the problem of ensuring a secret ballot.
The sweet lady who checks me into the local
school gym to vote could just as well be
doing that for someone casting a ballot in an
election clear across the country. The
various other mechanisms being discussed would
still be needed to provide the other desired
properties of such elections.
