You seem to indicate in your original message that you consider the
situation where 100 peasants can easily overwhelm one tough opponent a
problem. E.g., if 100 peasants fight 1 chimera, the chimera loses
every time.
If you consider this a problem, the 4:1 rule will fix it. If we
consider a "round" of combat to be one blow for the chimera and
however many for the peasants, then under the current system, the
peasants have a 82% chance per round to kill the chimera, so the
chimera is expected to last about 1-2 rounds, killing about 1-2
peasants. Under the 4:1 rule, the peasants only have a 5% chance to
kill the chimera per round, so the chimera is expected to last 20
rounds, killing 20 peasants. (Of course, the changing numbers of
peasants affects this somewhat.)
-- Scott T.