Actually the point was, "Ranma's opponents won't be worth bothering 
with".  If you want to upgun the opposition, first you'd have to come up 
with a plausible reason why the same single change doesn't just give 
Ranma more power but also attracts more poweful opposition.  For 
example, just because because Ranma turns into a saber toothed tiger 
with the power of the Cat Fist, is no reason in itself why he should 
attract godlike opponents from another universe.  With cyborg immortal 
Ranma he has had more time and space to make more powerful enemies...but 
given that he now has trouble leaving his opponents alive...won't they 
be dead?  Even then, there's more than enough creeping escalation in the 
original Ranma storyline without souping it up yet further.