I think having multiple sentences is an automatic
"check". Unless you aren't familiar with the subject or
don't do sufficient research, the tossup naturally
takes the proper shape. It also lets you specify
further - an anecdote about Shi Huang Ti's life also
keeps people from buzzing off the year (admittedly not
a great idea since there was no pronoun at that
point) and giving the dynasty.
On a different
note, it also cuts down on the sheer number of clues.
We've all experienced the "boredom" of sitting through
clues we don't know, but those additional clues provide
further differentiation to separate out teams that know
more about the topic from those who know less - which
is, as far as I can tell, the point of
tossups.
Matt Schneller